1

Schedule

of

Investments

Principal

Active

High

Yield

ETF

March

31,

2024

(unaudited)

See

accompanying

notes.

BONDS

-

87

.07

%

Principal

Amount

Value

Aerospace

&

Defense

-

1

.34

%

—

—

Bombardier,

Inc.

7.25%,

07/01/2031

(a)

$

290,000‌

$

290,590‌

7.50%,

02/01/2029

(a)

820,000‌

844,382‌

8.75%,

11/15/2030

(a)

1,072,000‌

1,144,656‌

$

2,279,628‌

Airlines

-

0

.05

%

United

Airlines

Pass-Through

Trust

,

Series

2016-

1

,

Class

B

3.65%,

07/07/2027

86,529‌

82,325‌

Auto

Parts

&

Equipment

-

2

.05

%

Dana,

Inc.

4.25%,

09/01/2030

1,735,000‌

1,533,113‌

Phinia,

Inc.

6.75%,

04/15/2029

(a)

115,000‌

116,109‌

Tenneco,

Inc.

8.00%,

11/17/2028

(a)

2,010,000‌

1,834,001‌

$

3,483,223‌

Banks

-

2

.90

%

Barclays

PLC

(5-year

Treasury

Constant

Maturity

Rate

+

5.43%),

8.00%,

03/15/2029

(b),(c)

2,416,000‌

2,411,021‌

JPMorgan

Chase

&

Co.

,

Series

HH

(3-month

Term

Secured

Overnight

Financing

Rate

+

3.13%),

4.60%,

02/01/2025

(b),(c)

2,556,000‌

2,512,838‌

$

4,923,859‌

Building

Materials

-

2

.89

%

AmeriTex

HoldCo

Intermediate

LLC

10.25%,

10/15/2028

(a)

2,283,000‌

2,451,157‌

Smyrna

Ready

Mix

Concrete

LLC

6.00%,

11/01/2028

(a)

2,518,000‌

2,460,985‌

$

4,912,142‌

Chemicals

-

4

.47

%

Consolidated

Energy

Finance

SA

5.63%,

10/15/2028

(a)

1,625,000‌

1,363,764‌

12.00%,

02/15/2031

(a)

815,000‌

851,153‌

Kobe

U.S.

Midco

2,

Inc.

9.25%,

PIK

10.00%,

11/01/2026

(a),(d)

2,218,650‌

1,891,399‌

Olympus

Water

U.S.

Holding

Corp.

6.25%,

10/01/2029

(a),(e)

2,730,000‌

2,498,760‌

Tronox,

Inc.

4.63%,

03/15/2029

(a)

1,107,000‌

992,908‌

$

7,597,984‌

Commercial

Services

-

3

.36

%

Albion

Financing

1

SARL/Aggreko

Holdings,

Inc.

6.13%,

10/15/2026

(a)

1,394,000‌

1,381,263‌

Garda

World

Security

Corp.

6.00%,

06/01/2029

(a)

1,116,000‌

998,869‌

9.50%,

11/01/2027

(a)

1,449,000‌

1,452,486‌

WASH

Multifamily

Acquisition,

Inc.

5.75%,

04/15/2026

(a)

1,921,000‌

1,877,532‌

$

5,710,150‌

Computers

-

2

.62

%

McAfee

Corp.

7.38%,

02/15/2030

(a)

575,000‌

527,302‌

NCR

Atleos

Corp.

9.50%,

04/01/2029

(a)

1,505,000‌

1,609,761‌

Seagate

HDD

Cayman

5.75%,

12/01/2034

880,000‌

860,834‌

9.63%,

12/01/2032

1,284,119‌

1,462,994‌

$

4,460,891‌

Distribution

&

Wholesale

-

0

.97

%

Verde

Purchaser

LLC

10.50%,

11/30/2030

(a)

1,566,000‌

1,648,823‌

BONDS

(continued)

Principal

Amount

Value

Diversified

Financial

Services

-

7

.39

%

AerCap

Holdings

NV

(5-year

Treasury

Constant

Maturity

Rate

+

4.54%),

5.88%,

10/10/2079

(c)

$

2,410,000‌

$

2,392,726‌

Credit

Acceptance

Corp.

9.25%,

12/15/2028

(a)

2,313,000‌

2,487,819‌

Global

Aircraft

Leasing

Co.

Ltd.

6.50%,

PIK

7.25%,

09/15/2024

(a),(d)

2,544,562‌

2,420,205‌

Macquarie

Airfinance

Holdings

Ltd.

8.13%,

03/30/2029

(a)

1,295,000‌

1,369,620‌

8.38%,

05/01/2028

(a)

1,363,000‌

1,444,734‌

OneMain

Finance

Corp.

3.50%,

01/15/2027

180,000‌

167,094‌

4.00%,

09/15/2030

2,254,000‌

1,929,077‌

6.63%,

01/15/2028

344,000‌

345,105‌

$

12,556,380‌

Electric

-

4

.23

%

Clearway

Energy

Operating

LLC

3.75%,

02/15/2031

(a)

2,611,000‌

2,240,995‌

GenOn

Energy,

Inc.

0.00%,

10/15/2020

(f),(g),(h)

3,100,000‌

—‌

NextEra

Energy

Operating

Partners

LP

7.25%,

01/15/2029

(a)

785,000‌

803,183‌

NRG

Energy,

Inc.

3.63%,

02/15/2031

(a)

1,339,000‌

1,155,500‌

3.88%,

02/15/2032

(a)

161,000‌

137,967‌

(5-year

Treasury

Constant

Maturity

Rate

+

5.92%),

10.25%,

03/15/2028

(a),(b),(c)

327,000‌

350,776‌

Vistra

Corp.

(5-year

Treasury

Constant

Maturity

Rate

+

5.74%),

7.00%,

12/15/2026

(a),(b),(c)

997,000‌

987,175‌

Vistra

Operations

Co.

LLC

4.38%,

05/01/2029

(a)

1,641,000‌

1,520,197‌

$

7,195,793‌

Electronics

-

0

.85

%

Sensata

Technologies,

Inc.

3.75%,

02/15/2031

(a)

1,664,000‌

1,439,363‌

Entertainment

-

7

.71

%

Boyne

USA,

Inc.

4.75%,

05/15/2029

(a)

1,980,000‌

1,835,405‌

Caesars

Entertainment,

Inc.

6.50%,

02/15/2032

(a)

2,387,000‌

2,408,020‌

CCM

Merger,

Inc.

6.38%,

05/01/2026

(a)

2,243,000‌

2,240,920‌

Churchill

Downs,

Inc.

5.75%,

04/01/2030

(a)

2,431,000‌

2,346,648‌

Cinemark

USA,

Inc.

5.25%,

07/15/2028

(a),(e)

1,931,000‌

1,827,987‌

Lions

Gate

Capital

Holdings

LLC

5.50%,

04/15/2029

(a)

1,959,000‌

1,498,707‌

Wynn

Resorts

Finance

LLC/Wynn

Resorts

Capital

Corp.

7.13%,

02/15/2031

(a)

912,000‌

943,825‌

$

13,101,512‌

Food

-

2

.65

%

Chobani

LLC/Chobani

Finance

Corp.,

Inc.

7.63%,

07/01/2029

(a)

2,059,000‌

2,087,312‌

Fiesta

Purchaser,

Inc.

7.88%,

03/01/2031

(a)

390,000‌

402,753‌

Pilgrim's

Pride

Corp.

3.50%,

03/01/2032

2,073,000‌

1,756,909‌

4.25%,

04/15/2031

277,000‌

249,699‌

$

4,496,673‌

Forest

Products

&

Paper

-

0

.44

%

Mercer

International,

Inc.

5.13%,

02/01/2029

774,000‌

680,325‌

2

Schedule

of

Investments

Principal

Active

High

Yield

ETF

March

31,

2024

(unaudited)

See

accompanying

notes.

BONDS

(continued)

Principal

Amount

Value

Forest

Products

&

Paper

(continued)

Mercer

International,

Inc.

(continued)

12.88%,

10/01/2028

(a)

$

55,000‌

$

60,088‌

$

740,413‌

Healthcare

-

Services

-

2

.55

%

Acadia

Healthcare

Co.,

Inc.

5.00%,

04/15/2029

(a)

2,516,000‌

2,390,697‌

Tenet

Healthcare

Corp.

6.13%,

06/15/2030

1,943,000‌

1,938,543‌

$

4,329,240‌

Home

Builders

-

2

.24

%

Adams

Homes,

Inc.

9.25%,

10/15/2028

(a)

1,541,000‌

1,598,721‌

Forestar

Group,

Inc.

3.85%,

05/15/2026

(a)

362,000‌

345,707‌

5.00%,

03/01/2028

(a)

1,929,000‌

1,854,748‌

$

3,799,176‌

Household

Products

&

Wares

-

0

.99

%

Kronos

Acquisition

Holdings,

Inc./KIK

Custom

Products,

Inc.

5.00%,

12/31/2026

(a)

540,000‌

529,341‌

7.00%,

12/31/2027

(a)

1,170,000‌

1,162,232‌

$

1,691,573‌

Insurance

-

1

.16

%

Acrisure

LLC/Acrisure

Finance,

Inc.

6.00%,

08/01/2029

(a)

2,146,000‌

1,968,051‌

Investment

Companies

-

2

.52

%

Compass

Group

Diversified

Holdings

LLC

5.25%,

04/15/2029

(a)

2,147,000‌

2,039,934‌

Icahn

Enterprises

LP/Icahn

Enterprises

Finance

Corp.

4.38%,

02/01/2029

2,640,000‌

2,250,845‌

$

4,290,779‌

Iron

&

Steel

-

1

.02

%

TMS

International

Corp.

6.25%,

04/15/2029

(a)

1,901,000‌

1,735,120‌

Lodging

-

0

.48

%

Wynn

Macau

Ltd.

5.63%,

08/26/2028

(a)

868,000‌

822,713‌

Machinery

-

Diversified

-

1

.27

%

Maxim

Crane

Works

Holdings

Capital

LLC

11.50%,

09/01/2028

(a)

1,991,000‌

2,158,642‌

Media

-

3

.94

%

CSC

Holdings

LLC

4.50%,

11/15/2031

(a)

1,199,000‌

848,852‌

Directv

Financing

LLC

8.88%,

02/01/2030

(a)

128,000‌

127,691‌

Directv

Financing

LLC/Directv

Financing

Co.-

Obligor,

Inc.

5.88%,

08/15/2027

(a)

2,230,000‌

2,109,661‌

DISH

DBS

Corp.

5.13%,

06/01/2029

278,000‌

115,950‌

5.25%,

12/01/2026

(a)

13,284‌

10,460‌

7.38%,

07/01/2028

1,166,000‌

561,344‌

DISH

Network

Corp.

11.75%,

11/15/2027

(a)

1,640,000‌

1,674,327‌

Scripps

Escrow

II,

Inc.

5.38%,

01/15/2031

(a)

704,000‌

433,148‌

Sunrise

HoldCo

IV

BV

5.50%,

01/15/2028

(a)

844,000‌

810,338‌

$

6,691,771‌

Mining

-

1

.38

%

Taseko

Mines

Ltd.

7.00%,

02/15/2026

(a)

2,331,000‌

2,340,536‌

Oil

&

Gas

-

5

.25

%

Aethon

United

BR

LP/Aethon

United

Finance

Corp.

8.25%,

02/15/2026

(a)

1,904,000‌

1,925,970‌

Civitas

Resources,

Inc.

8.63%,

11/01/2030

(a)

1,499,000‌

1,609,592‌

BONDS

(continued)

Principal

Amount

Value

Oil

&

Gas

(continued)

Comstock

Resources,

Inc.

5.88%,

01/15/2030

(a)

$

2,325,000‌

$

2,105,539‌

Diamond

Foreign

Asset

Co./Diamond

Finance

LLC

8.50%,

10/01/2030

(a)

1,566,000‌

1,652,769‌

Vital

Energy,

Inc.

9.75%,

10/15/2030

1,483,000‌

1,621,732‌

$

8,915,602‌

Oil

&

Gas

Services

-

1

.33

%

Archrock

Partners

LP/Archrock

Partners

Finance

Corp.

6.25%,

04/01/2028

(a)

1,643,000‌

1,625,646‌

Kodiak

Gas

Services

LLC

7.25%,

02/15/2029

(a)

630,000‌

641,710‌

$

2,267,356‌

Packaging

&

Containers

-

1

.40

%

Clydesdale

Acquisition

Holdings,

Inc.

6.63%,

04/15/2029

(a)

203,000‌

202,837‌

8.75%,

04/15/2030

(a)

725,000‌

712,341‌

LABL,

Inc.

5.88%,

11/01/2028

(a)

404,000‌

371,520‌

8.25%,

11/01/2029

(a),(e)

673,000‌

574,315‌

9.50%,

11/01/2028

(a)

518,000‌

523,985‌

$

2,384,998‌

Pharmaceuticals

-

3

.78

%

AdaptHealth

LLC

5.13%,

03/01/2030

(a)

2,064,000‌

1,800,089‌

BellRing

Brands,

Inc.

7.00%,

03/15/2030

(a)

1,581,000‌

1,628,575‌

Jazz

Securities

DAC

4.38%,

01/15/2029

(a)

2,273,000‌

2,117,385‌

Owens

&

Minor,

Inc.

4.50%,

03/31/2029

(a),(e)

955,000‌

874,479‌

$

6,420,528‌

Pipelines

-

4

.86

%

DT

Midstream,

Inc.

4.13%,

06/15/2029

(a)

1,796,000‌

1,651,120‌

Genesis

Energy

LP/Genesis

Energy

Finance

Corp.

8.25%,

01/15/2029

1,607,000‌

1,649,740‌

Hess

Midstream

Operations

LP

4.25%,

02/15/2030

(a)

2,208,000‌

2,028,948‌

NGL

Energy

Operating

LLC/NGL

Energy

Finance

Corp.

8.13%,

02/15/2029

(a)

350,000‌

358,464‌

8.38%,

02/15/2032

(a)

930,000‌

953,349‌

Venture

Global

LNG,

Inc.

8.38%,

06/01/2031

(a)

143,000‌

147,471‌

9.50%,

02/01/2029

(a)

1,365,000‌

1,471,283‌

$

8,260,375‌

REITs

-

2

.80

%

CBL

&

Associates

LP

0.00%,

12/15/2026

(f),(g),(h)

6,000,000‌

—‌

HAT

Holdings

I

LLC/HAT

Holdings

II

LLC

3.38%,

06/15/2026

(a)

1,175,000‌

1,106,738‌

3.75%,

09/15/2030

(a)

550,000‌

461,944‌

8.00%,

06/15/2027

(a)

364,000‌

379,543‌

Ladder

Capital

Finance

Holdings

LLLP/Ladder

Capital

Finance

Corp.

4.75%,

06/15/2029

(a)

3,091,000‌

2,809,809‌

$

4,758,034‌

Retail

-

3

.28

%

Bath

&

Body

Works,

Inc.

5.25%,

02/01/2028

344,000‌

336,895‌

6.63%,

10/01/2030

(a)

567,000‌

579,190‌

6.75%,

07/01/2036

297,000‌

299,974‌

9.38%,

07/01/2025

(a)

30,000‌

31,302‌

3

Schedule

of

Investments

Principal

Active

High

Yield

ETF

March

31,

2024

(unaudited)

See

accompanying

notes.

BONDS

(continued)

Principal

Amount

Value

Retail

(continued)

Fertitta

Entertainment

LLC/Fertitta

Entertainment

Finance

Co.,

Inc.

4.63%,

01/15/2029

(a)

$

995,000‌

$

912,391‌

6.75%,

01/15/2030

(a)

731,000‌

656,374‌

LSF9

Atlantis

Holdings

LLC/Victra

Finance

Corp.

7.75%,

02/15/2026

(a)

2,062,000‌

2,043,414‌

Park

River

Holdings,

Inc.

5.63%,

02/01/2029

(a)

840,000‌

714,197‌

$

5,573,737‌

Software

-

0

.96

%

Cloud

Software

Group,

Inc.

6.50%,

03/31/2029

(a)

1,715,000‌

1,627,469‌

Telecommunications

-

0

.96

%

Frontier

Communications

Holdings

LLC

8.63%,

03/15/2031

(a)

1,305,000‌

1,332,834‌

Level

3

Financing,

Inc.

10.50%,

05/15/2030

(a)

295,000‌

301,638‌

$

1,634,472‌

Transportation

-

0

.98

%

Watco

Cos.

LLC/Watco

Finance

Corp.

6.50%,

06/15/2027

(a)

1,681,000‌

1,661,522‌

TOTAL

BONDS

a

$

147,960,853‌

SENIOR

FLOATING

RATE

INTERESTS

-

5

.63

%

Principal

Amount

Value

Airlines

-

2

.30

%

–

—

American

Airlines,

Inc.,

Series

2021

Term

Loan

(3-month

Term

Secured

Overnight

Financing

Rate

+

4.75%),

10.33%,

04/20/2028

$

1,151,750‌

$

1,194,780‌

United

Airlines,

Inc.,

Series

2024

Term

Loan

B

(3-month

Term

Secured

Overnight

Financing

Rate

+

2.75%),

8.08%,

02/15/2031

1,147,273‌

1,147,089‌

WestJet

Loyalty

LP,

Series

Term

Loan

B

(3-month

Term

Secured

Overnight

Financing

Rate

+

3.75%),

9.06%,

02/14/2031

1,560,000‌

1,558,705‌

$

3,900,574‌

Auto

Parts

&

Equipment

-

0

.13

%

Tenneco,

Inc.,

Series

2022

Term

Loan

B

(3-month

Term

Secured

Overnight

Financing

Rate

+

5.00%),

10.42%-10.45%,

11/17/2028

225,000‌

211,349‌

Food

-

1

.21

%

Fiesta

Purchaser,

Inc.,

Series

2024

Term

Loan

B

(3-month

Term

Secured

Overnight

Financing

Rate

+

4.00%),

9.32%,

02/12/2031

2,055,000‌

2,057,281‌

Forest

Products

&

Paper

-

0

.65

%

Spectrum

Group

Buyer,

Inc.,

Series

2022

Term

Loan

B

(3-month

Term

Secured

Overnight

Financing

Rate

+

6.50%),

11.81%,

05/19/2028

1,359,456‌

1,107,956‌

Healthcare

-

Services

-

0

.81

%

Star

Parent,

Inc.,

Series

Term

Loan

B

(3-month

Term

Secured

Overnight

Financing

Rate

+

4.00%),

9.31%,

09/27/2030

1,385,000‌

1,375,651‌

SENIOR

FLOATING

RATE

INTERESTS

(continued)

Principal

Amount

Value

Mining

-

0

.53

%

Arsenal

AIC

Parent

LLC

(1-month

Term

Secured

Overnight

Financing

Rate

+

4.50%),

9.83%,

08/18/2030

$

902,738‌

$

904,769‌

TOTAL

SENIOR

FLOATING

RATE

INTERESTS

a

$

9,557,580‌

U.S.

GOVERNMENT

&

GOVERNMENT

AGENCY

OBLIGATIONS

-

0

.90

%

Principal

Amount

Value

U.S.

Treasury

-

0

.90

%

–

–

3.50%,

04/30/2028

$

1,583,200‌

$

1,535,766‌

TOTAL

U.S.

GOVERNMENT

&

GOVERNMENT

AGENCY

OBLIGATIONS

a

$

1,535,766‌

INVESTMENT

COMPANIES

-

8

.25

%

Shares

Held

Value

Money

Market

Funds

-

8

.25

%

-

—

Principal

Government

Money

Market

Fund,

Class

R-6

5.22%

(i),(j),(k)

3,552,910‌

$

3,552,910‌

State

Street

Institutional

U.S.

Government

Money

Market

Fund,

Premier

Class

5.26%

(i)

10,471,192‌

10,471,192‌

TOTAL

INVESTMENT

COMPANIES

a

$

14,024,102‌

Total

Investments

$

173,078,301‌

Other

Assets

and

Liabilities

-

(1.85%)

(

3,145,350‌

)

TOTAL

NET

ASSETS

-

100.00%

$

169,932,951‌

(a)

Security

exempt

from

registration

under

Rule

144A

of

the

Securities

Act

of

1933.

These

securities

may

be

resold

in

transactions

exempt

from

registration,

normally

to

qualified

institutional

buyers.

At

the

end

of

the

period,

the

value

of

these

securities

totaled

$122,801,770

or

72.26%

of

net

assets.

(b)

Perpetual

security.

Perpetual

securities

pay

an

indefinite

stream

of

interest,

but

they

may

be

called

by

the

issuer

at

an

earlier

date.

Date

shown,

if

any,

reflects

the

next

call

date

or

final

legal

maturity

date.

Rate

shown

is

as

of

period

end.

(c)

Rate

shown

is

as

of

period

end.

The

rate

may

be

a

variable

or

floating

rate

or

a

fixed

rate

which

may

convert

to

a

variable

or

floating

rate

in

the

future.

(d)

Payment

in

kind;

the

issuer

has

the

option

of

paying

additional

securities

in

lieu

of

cash.

(e)

Security

or

a

portion

of

the

security

was

on

loan.

At

the

end

of

the

period,

the

value

of

these

securities

totaled

$3,490,041

or

2.05%

of

net

assets.

(f)

Security

is

defaulted.

(g)

Non-income

producing

security.

(h)

The

value

of

these

investments

was

determined

using

significant

unobservable

inputs,

in

good

faith

by

the

Advisor,

under

procedures

established

and

periodically

reviewed

by

the

Board

of

Trustees.

(i)

1-day

yield

shown

as

of

period

end.

(j)

Affiliated

Security.

Security

is

either

an

affiliate

(and

registered

under

the

Investment

Company

Act

of

1940)

or

an

affiliate

as

defined

by

the

Investment

Company

Act

of

1940

(controls

5.00%

or

more

of

the

outstanding

voting

shares

of

the

security).

Please

see

Affiliated

Securities

sub-schedule

for

transactional

information.

(k)

Security

or

a

portion

of

the

security

was

received

as

collateral

for

securities

lending.

At

the

end

of

the

period,

the

value

of

these

securities

totaled

$3,552,910

or

2.09%

of

net

assets.

Portfolio

Summary

Sector

Percent

Consumer,

Cyclical

19.21%

Financial

16.77%

Consumer,

Non-cyclical

15.35%

Energy

11.44%

Industrial

8.73%

Basic

Materials

8.49%

Money

Market

Funds

8.25%

Communications

4.90%

Utilities

4.23%

Technology

3.58%

Government

0.90%

Other

Assets

and

Liabilities

(1.85)%

TOTAL

NET

ASSETS

100.00%

4

Schedule

of

Investments

Principal

Active

High

Yield

ETF

March

31,

2024

(unaudited)

See

accompanying

notes.

Affiliated

Securities

June

30,

2023

Value

Purchases

Cost

Sales

Proceeds

March

31,

2024

Value

Principal

Government

Money

Market

Fund,

Class

R-6

5.22%

$

3,219,013‌

$

20,679,700‌

$

20,345,803‌

$

3,552,910‌

$

3,219,013‌

$

20,679,700‌

$

20,345,803‌

$

3,552,910‌

a

a

Income

(a)

Realized

Gain/(Loss)

on

Investments

Realized

Gain

from

Capital

Gain

Distributions

Change

in

Unrealized

Gain/(Loss)

Principal

Government

Money

Market

Fund,

Class

R-6

5.22%

$

—‌

$

—‌

$

—‌

$

—‌

$

—‌

$

—‌

$

—‌

$

—‌

(a)

Amount

excludes

earnings

from

securities

lending

collateral.

5

Schedule

of

Investments

Principal

Focused

Blue

Chip

ETF

March

31,

2024

(unaudited)

See

accompanying

notes.

COMMON

STOCKS

-

99

.92

%

Shares

Held

Value

Aerospace

&

Defense

-

4

.71

%

-

—

TransDigm

Group,

Inc.

1,456‌

$

1,793,210‌

Commercial

Services

-

5

.31

%

CoStar

Group,

Inc.

(a)

13,779‌

1,331,051‌

Moody's

Corp.

1,761‌

692,126‌

$

2,023,177‌

Distribution

&

Wholesale

-

2

.25

%

Copart,

Inc.

(a)

14,773‌

855,652‌

Diversified

Financial

Services

-

13

.90

%

Charles

Schwab

Corp.

12,260‌

886,888‌

Mastercard,

Inc.,

Class

A

5,702‌

2,745,912‌

Visa,

Inc.,

Class

A

5,956‌

1,662,201‌

$

5,295,001‌

Healthcare

-

Products

-

4

.43

%

Danaher

Corp.

6,765‌

1,689,356‌

Insurance

-

4

.70

%

Progressive

Corp.

8,667‌

1,792,509‌

Internet

-

24

.43

%

Alphabet,

Inc.,

Class

C

(a)

27,780‌

4,229,783‌

Amazon.com,

Inc.

(a)

25,000‌

4,509,500‌

Netflix,

Inc.

(a)

933‌

566,639‌

$

9,305,922‌

Lodging

-

2

.90

%

Hilton

Worldwide

Holdings,

Inc.

5,184‌

1,105,799‌

Pharmaceuticals

-

1

.42

%

Zoetis,

Inc.

3,205‌

542,318‌

Private

Equity

-

4

.60

%

Brookfield

Corp.,

Class

A

41,821‌

1,751,045‌

REITs

-

2

.82

%

American

Tower

Corp.

5,437‌

1,074,297‌

Retail

-

2

.27

%

O'Reilly

Automotive,

Inc.

(a)

766‌

864,722‌

COMMON

STOCKS

(continued)

Shares

Held

Value

Software

-

23

.34

%

Adobe,

Inc.

(a)

2,555‌

$

1,289,253‌

Intuit,

Inc.

2,060‌

1,339,000‌

Microsoft

Corp.

12,526‌

5,269,938‌

Roper

Technologies,

Inc.

1,776‌

996,052‌

$

8,894,243‌

Transportation

-

2

.84

%

Union

Pacific

Corp.

4,394‌

1,080,616‌

TOTAL

COMMON

STOCKS

a

$

38,067,867‌

INVESTMENT

COMPANIES

-

0

.01

%

Shares

Held

Value

Money

Market

Funds

-

0

.01

%

-

—

State

Street

Institutional

U.S.

Government

Money

Market

Fund,

Premier

Class

5.26%

(b)

5,611‌

$

5,611‌

TOTAL

INVESTMENT

COMPANIES

a

$

5,611‌

Total

Investments

$

38,073,478‌

Other

Assets

and

Liabilities

-

0.07%

25,219‌

TOTAL

NET

ASSETS

-

100.00%

$

38,098,697‌

(a)

Non-income

producing

security.

(b)

1-day

yield

shown

as

of

period

end.

Portfolio

Summary

Sector

Percent

Financial

26.02%

Communications

24.43%

Technology

23.34%

Consumer,

Non-cyclical

11.16%

Industrial

7.55%

Consumer,

Cyclical

7.42%

Money

Market

Funds

0.01%

Other

Assets

and

Liabilities

0.07%

TOTAL

NET

ASSETS

100.00%

Affiliated

Securities

June

30,

2023

Value

Purchases

Cost

Sales

Proceeds

March

31,

2024

Value

Principal

Government

Money

Market

Fund,

Class

R-6

5.22%

$

—‌

$

142,950‌

$

142,950‌

$

—‌

$

—‌

$

142,950‌

$

142,950‌

$

—‌

a

a

Income

(a)

Realized

Gain/(Loss)

on

Investments

Realized

Gain

from

Capital

Gain

Distributions

Change

in

Unrealized

Gain/(Loss)

Principal

Government

Money

Market

Fund,

Class

R-6

5.22%

$

—‌

$

—‌

$

—‌

$

—‌

$

—‌

$

—‌

$

—‌

$

—‌

(a)

Amount

excludes

earnings

from

securities

lending

collateral.

6

Schedule

of

Investments

Principal

Healthcare

Innovators

ETF

March

31,

2024

(unaudited)

See

accompanying

notes.

COMMON

STOCKS

-

99

.79

%

Shares

Held

Value

Biotechnology

-

62

.58

%

-

—

2seventy

bio,

Inc.

(a)

8,462‌

$

45,272‌

4D

Molecular

Therapeutics,

Inc.

(a)

4,739‌

150,985‌

Aadi

Bioscience,

Inc.

(a)

5,352‌

12,524‌

ACADIA

Pharmaceuticals,

Inc.

(a)

18,537‌

342,749‌

Adicet

Bio,

Inc.

(a)

8,568‌

20,135‌

ADMA

Biologics,

Inc.

(a)

30,964‌

204,362‌

Aerovate

Therapeutics,

Inc.

(a)

3,989‌

117,955‌

Agenus,

Inc.

(a)

44,794‌

25,981‌

Akero

Therapeutics,

Inc.

(a)

5,494‌

138,778‌

Allogene

Therapeutics,

Inc.

(a)

19,685‌

87,992‌

Allovir,

Inc.

(a)

14,327‌

10,815‌

Alnylam

Pharmaceuticals,

Inc.

(a)

7,218‌

1,078,730‌

Amicus

Therapeutics,

Inc.

(a)

32,450‌

382,261‌

AnaptysBio,

Inc.

(a)

4,135‌

93,120‌

Anavex

Life

Sciences

Corp.

(a)

11,574‌

58,912‌

ANI

Pharmaceuticals,

Inc.

(a)

2,530‌

174,899‌

Apellis

Pharmaceuticals,

Inc.

(a)

12,457‌

732,222‌

Arbutus

Biopharma

Corp.

(a)

25,400‌

65,532‌

Arcellx,

Inc.

(a)

5,747‌

399,704‌

Arcturus

Therapeutics

Holdings,

Inc.

(a)

3,773‌

127,414‌

Arcus

Biosciences,

Inc.

(a)

9,072‌

171,279‌

Arcutis

Biotherapeutics,

Inc.

(a)

8,492‌

84,156‌

Arrowhead

Pharmaceuticals,

Inc.

(a)

12,354‌

353,324‌

Atara

Biotherapeutics,

Inc.

(a)

16,865‌

11,704‌

Atea

Pharmaceuticals,

Inc.

(a)

16,386‌

66,199‌

Aurinia

Pharmaceuticals,

Inc.

(a)

17,062‌

85,481‌

Avidity

Biosciences,

Inc.

(a)

9,136‌

233,151‌

Axsome

Therapeutics,

Inc.

(a)

4,982‌

397,564‌

Beam

Therapeutics,

Inc.

(a)

8,533‌

281,930‌

BioCryst

Pharmaceuticals,

Inc.

(a)

23,519‌

119,477‌

Biohaven

Ltd.

(a)

9,084‌

496,804‌

Bio-Rad

Laboratories,

Inc.,

Class

A

(a)

3,146‌

1,088,107‌

Bluebird

Bio,

Inc.

(a),(b)

17,159‌

21,964‌

Blueprint

Medicines

Corp.

(a)

6,906‌

655,103‌

Bridgebio

Pharma,

Inc.

(a)

19,301‌

596,787‌

C4

Therapeutics,

Inc.

(a),(b)

13,238‌

108,155‌

Cara

Therapeutics,

Inc.

(a)

9,986‌

9,087‌

Caribou

Biosciences,

Inc.

(a)

12,418‌

63,829‌

Cassava

Sciences,

Inc.

(a),(b)

5,556‌

112,731‌

Celldex

Therapeutics,

Inc.

(a)

5,733‌

240,614‌

Cerevel

Therapeutics

Holdings,

Inc.

(a)

17,604‌

744,121‌

Chinook

Therapeutics,

Inc.

(a),(c)

9,493‌

3,797‌

Cogent

Biosciences,

Inc.

(a)

9,477‌

63,685‌

Crinetics

Pharmaceuticals,

Inc.

(a)

7,203‌

337,172‌

Cullinan

Oncology,

Inc.

(a)

6,456‌

110,010‌

Cytokinetics,

Inc.

(a)

10,792‌

756,627‌

Day

One

Biopharmaceuticals,

Inc.

(a)

9,741‌

160,921‌

Deciphera

Pharmaceuticals,

Inc.

(a)

9,858‌

155,066‌

Denali

Therapeutics,

Inc.

(a)

15,561‌

319,312‌

Design

Therapeutics,

Inc.

(a)

9,227‌

37,185‌

Dyne

Therapeutics,

Inc.

(a)

8,308‌

235,864‌

Edgewise

Therapeutics,

Inc.

(a)

10,183‌

185,738‌

Editas

Medicine,

Inc.

(a)

10,552‌

78,296‌

Emergent

BioSolutions,

Inc.

(a)

7,870‌

19,911‌

Erasca,

Inc.

(a)

25,478‌

52,485‌

Esperion

Therapeutics,

Inc.

(a)

29,151‌

78,125‌

Evolus,

Inc.

(a)

8,774‌

122,836‌

Fate

Therapeutics,

Inc.

(a)

14,375‌

105,513‌

FibroGen,

Inc.

(a)

11,293‌

26,539‌

Geron

Corp.

(a)

63,900‌

210,870‌

Gossamer

Bio,

Inc.

(a)

29,935‌

35,323‌

Ideaya

Biosciences,

Inc.

(a)

6,906‌

303,035‌

IGM

Biosciences,

Inc.

(a),(b)

5,265‌

50,807‌

Illumina,

Inc.

(a)

6,635‌

911,118‌

ImmunityBio,

Inc.

(a),(b)

56,126‌

301,397‌

Immunovant,

Inc.

(a)

15,532‌

501,839‌

Inhibrx,

Inc.

(a)

5,871‌

205,250‌

Inovio

Pharmaceuticals,

Inc.

(a)

4,938‌

68,539‌

Insmed,

Inc.

(a)

15,931‌

432,208‌

Intellia

Therapeutics,

Inc.

(a)

10,055‌

276,613‌

COMMON

STOCKS

(continued)

Shares

Held

Value

Biotechnology

(continued)

Intra-Cellular

Therapies,

Inc.

(a)

10,537‌

$

729,160‌

Ionis

Pharmaceuticals,

Inc.

(a)

15,890‌

688,832‌

Iovance

Biotherapeutics,

Inc.

(a)

28,431‌

421,347‌

Karyopharm

Therapeutics,

Inc.

(a)

17,929‌

27,073‌

Keros

Therapeutics,

Inc.

(a)

3,612‌

239,114‌

Kezar

Life

Sciences,

Inc.

(a)

14,867‌

13,404‌

Kiniksa

Pharmaceuticals

Ltd.,

Class

A

(a)

5,889‌

116,190‌

Kodiak

Sciences,

Inc.

(a)

10,735‌

56,466‌

Krystal

Biotech,

Inc.

(a)

3,053‌

543,220‌

Kymera

Therapeutics,

Inc.

(a)

6,617‌

266,003‌

Ligand

Pharmaceuticals,

Inc.

(a)

2,155‌

157,531‌

Liquidia

Corp.

(a)

10,675‌

157,456‌

MacroGenics,

Inc.

(a)

10,366‌

152,588‌

Mersana

Therapeutics,

Inc.

(a)

17,670‌

79,162‌

Mineralys

Therapeutics,

Inc.

(a)

6,002‌

77,486‌

Mural

Oncology

PLC

(a)

1,661‌

8,122‌

Myriad

Genetics,

Inc.

(a)

9,799‌

208,915‌

Nektar

Therapeutics

(a)

50,456‌

47,136‌

NGM

Biopharmaceuticals,

Inc.

(a)

15,170‌

24,120‌

Nkarta,

Inc.

(a)

10,734‌

116,035‌

Novavax,

Inc.

(a),(b)

11,877‌

56,772‌

Nurix

Therapeutics,

Inc.

(a)

7,517‌

110,500‌

Nuvalent,

Inc.,

Class

A

(a)

6,208‌

466,159‌

Phathom

Pharmaceuticals,

Inc.

(a)

6,953‌

73,841‌

Praxis

Precision

Medicines,

Inc.

(a)

1,970‌

120,209‌

Precigen,

Inc.

(a)

46,946‌

68,072‌

Prime

Medicine,

Inc.

(a)

12,314‌

86,198‌

Prothena

Corp.

PLC

(a)

6,064‌

150,205‌

PTC

Therapeutics,

Inc.

(a)

8,315‌

241,883‌

RAPT

Therapeutics,

Inc.

(a)

4,826‌

43,338‌

Recursion

Pharmaceuticals,

Inc.,

Class

A

(a),(b)

24,092‌

240,197‌

REGENXBIO,

Inc.

(a)

5,998‌

126,378‌

Relay

Therapeutics,

Inc.

(a)

14,959‌

124,160‌

Replimune

Group,

Inc.

(a)

7,347‌

60,025‌

REVOLUTION

Medicines,

Inc.

(a)

12,205‌

393,367‌

Rigel

Pharmaceuticals,

Inc.

(a)

39,688‌

58,738‌

Rocket

Pharmaceuticals,

Inc.

(a)

9,854‌

265,467‌

Sage

Therapeutics,

Inc.

(a)

6,896‌

129,231‌

Sana

Biotechnology,

Inc.

(a)

25,357‌

253,570‌

Sangamo

Therapeutics,

Inc.

(a)

35,597‌

23,857‌

Sarepta

Therapeutics,

Inc.

(a)

9,547‌

1,235,955‌

Scilex

Holding

Co.

(a)

10,078‌

16,024‌

Seer,

Inc.

(a)

11,819‌

22,456‌

SpringWorks

Therapeutics,

Inc.

(a)

7,738‌

380,864‌

Stoke

Therapeutics,

Inc.

(a)

7,250‌

97,875‌

Sutro

Biopharma,

Inc.

(a)

11,598‌

65,529‌

Syndax

Pharmaceuticals,

Inc.

(a)

8,505‌

202,419‌

TG

Therapeutics,

Inc.

(a)

16,730‌

254,463‌

Theravance

Biopharma,

Inc.

(a),(b)

9,160‌

82,165‌

Travere

Therapeutics,

Inc.

(a)

8,996‌

69,359‌

Ultragenyx

Pharmaceutical,

Inc.

(a)

8,080‌

377,255‌

Ventyx

Biosciences,

Inc.

(a)

6,888‌

37,884‌

Vera

Therapeutics,

Inc.

(a)

8,499‌

366,477‌

Veracyte,

Inc.

(a)

8,802‌

195,052‌

Vericel

Corp.

(a)

5,885‌

306,138‌

Verve

Therapeutics,

Inc.

(a)

8,128‌

107,940‌

Vir

Biotechnology,

Inc.

(a)

15,192‌

153,895‌

Viridian

Therapeutics,

Inc.

(a)

5,445‌

95,342‌

Xencor,

Inc.

(a)

7,290‌

161,328‌

Zentalis

Pharmaceuticals,

Inc.

(a)

7,566‌

119,240‌

$

27,927,177‌

Chemicals

-

0

.10

%

Codexis,

Inc.

(a)

12,992‌

45,342‌

Healthcare

-

Products

-

22

.57

%

10X

Genomics,

Inc.,

Class

A

(a)

10,803‌

405,437‌

Adaptive

Biotechnologies

Corp.

(a)

18,281‌

58,682‌

Alphatec

Holdings,

Inc.

(a)

13,592‌

187,434‌

AngioDynamics,

Inc.

(a)

6,975‌

40,943‌

Artivion,

Inc.

(a)

6,071‌

128,462‌

AtriCure,

Inc.

(a)

5,574‌

169,561‌

7

Schedule

of

Investments

Principal

Healthcare

Innovators

ETF

March

31,

2024

(unaudited)

See

accompanying

notes.

COMMON

STOCKS

(continued)

Shares

Held

Value

Healthcare

-

Products

(continued)

Axogen,

Inc.

(a)

7,442‌

$

60,057‌

Axonics,

Inc.

(a)

5,743‌

396,095‌

Azenta,

Inc.

(a)

7,950‌

479,226‌

BioLife

Solutions,

Inc.

(a)

5,874‌

108,963‌

Bionano

Genomics,

Inc.

(a)

5,950‌

6,604‌

Butterfly

Network,

Inc.

(a),(b)

27,115‌

29,284‌

CareDx,

Inc.

(a)

8,739‌

92,546‌

Cerus

Corp.

(a)

28,590‌

54,035‌

Cutera,

Inc.

(a)

2,703‌

3,973‌

Exact

Sciences

Corp.

(a)

19,311‌

1,333,618‌

Glaukos

Corp.

(a)

5,616‌

529,533‌

ICU

Medical,

Inc.

(a)

2,694‌

289,120‌

Inari

Medical,

Inc.

(a)

6,151‌

295,125‌

Inogen,

Inc.

(a)

4,514‌

36,428‌

Inotiv,

Inc.

(a),(b)

7,469‌

81,711‌

Inspire

Medical

Systems,

Inc.

(a)

3,180‌

683,032‌

iRhythm

Technologies,

Inc.

(a)

3,397‌

394,052‌

MaxCyte,

Inc.

(a)

16,156‌

67,694‌

MiMedx

Group,

Inc.

(a)

19,157‌

147,509‌

Natera,

Inc.

(a)

12,505‌

1,143,707‌

Nevro

Corp.

(a)

4,571‌

66,005‌

Novocure

Ltd.

(a)

11,615‌

181,542‌

OmniAb,

Inc.

(a)

19,080‌

103,414‌

OmniAb,

Inc.,

Earnout

Shares

(a)

977‌

—‌

OmniAb,

Inc.,

Earnout

Shares

(a)

977‌

—‌

Orthofix

Medical,

Inc.

(a)

5,038‌

73,152‌

OrthoPediatrics

Corp.

(a)

2,978‌

86,838‌

Pacific

Biosciences

of

California,

Inc.

(a)

28,630‌

107,363‌

Paragon

28,

Inc.

(a)

10,476‌

129,379‌

PROCEPT

BioRobotics

Corp.

(a)

5,486‌

271,118‌

Pulmonx

Corp.

(a)

5,731‌

53,126‌

Quanterix

Corp.

(a)

5,998‌

141,313‌

Quantum-Si,

Inc.

(a),(b)

29,252‌

57,626‌

RxSight,

Inc.

(a)

5,073‌

261,665‌

SI-BONE,

Inc.

(a)

4,868‌

79,689‌

Silk

Road

Medical,

Inc.

(a)

4,561‌

83,558‌

Surmodics,

Inc.

(a)

2,596‌

76,167‌

Tactile

Systems

Technology,

Inc.

(a)

3,758‌

61,067‌

Tandem

Diabetes

Care,

Inc.

(a)

7,836‌

277,473‌

TransMedics

Group,

Inc.

(a)

3,715‌

274,687‌

Treace

Medical

Concepts,

Inc.

(a)

7,217‌

94,182‌

Twist

Bioscience

Corp.

(a)

7,957‌

273,005‌

Zimvie,

Inc.

(a)

5,925‌

97,703‌

$

10,072,903‌

Healthcare

-

Services

-

0

.21

%

Nano-X

Imaging

Ltd.

(a),(b)

9,581‌

93,606‌

Pharmaceuticals

-

14

.05

%

AbCellera

Biologics,

Inc.

(a),(b)

34,204‌

154,944‌

Aclaris

Therapeutics,

Inc.

(a)

8,922‌

11,063‌

Agios

Pharmaceuticals,

Inc.

(a)

7,034‌

205,674‌

Alector,

Inc.

(a)

12,786‌

76,972‌

Alkermes

PLC

(a)

18,350‌

496,734‌

Amneal

Pharmaceuticals,

Inc.

(a)

32,292‌

195,690‌

Amylyx

Pharmaceuticals,

Inc.

(a)

7,836‌

22,254‌

Anika

Therapeutics,

Inc.

(a)

2,482‌

63,043‌

Arvinas,

Inc.

(a)

6,582‌

271,705‌

Bioxcel

Therapeutics,

Inc.

(a)

3,777‌

10,651‌

Coherus

Biosciences,

Inc.

(a)

10,390‌

24,832‌

Collegium

Pharmaceutical,

Inc.

(a)

4,762‌

184,861‌

Elanco

Animal

Health,

Inc.

(a)

54,828‌

892,600‌

Enanta

Pharmaceuticals,

Inc.

(a)

2,938‌

51,297‌

COMMON

STOCKS

(continued)

Shares

Held

Value

Pharmaceuticals

(continued)

Fulcrum

Therapeutics,

Inc.

(a)

16,233‌

$

153,239‌

Heron

Therapeutics,

Inc.

(a)

22,233‌

61,585‌

KalVista

Pharmaceuticals,

Inc.

(a)

6,622‌

78,537‌

Kura

Oncology,

Inc.

(a)

9,668‌

206,218‌

Lyell

Immunopharma,

Inc.

(a)

37,936‌

84,597‌

Madrigal

Pharmaceuticals,

Inc.

(a)

2,013‌

537,552‌

MannKind

Corp.

(a)

34,089‌

154,423‌

Mirum

Pharmaceuticals,

Inc.

(a)

4,999‌

125,575‌

Morphic

Holding,

Inc.

(a)

4,786‌

168,467‌

Ocugen,

Inc.

(a),(b)

59,354‌

97,341‌

Ocular

Therapeutix,

Inc.

(a)

12,337‌

112,267‌

Perrigo

Co.

PLC

15,067‌

485,007‌

PMV

Pharmaceuticals,

Inc.

(a)

9,331‌

15,863‌

Protagonist

Therapeutics,

Inc.

(a)

7,074‌

204,651‌

Revance

Therapeutics,

Inc.

(a)

9,117‌

44,856‌

Senseonics

Holdings,

Inc.

(a)

92,985‌

49,384‌

Seres

Therapeutics,

Inc.

(a)

14,929‌

11,557‌

SIGA

Technologies,

Inc.

12,178‌

104,244‌

Vaxcyte,

Inc.

(a)

10,328‌

705,506‌

Xeris

Biopharma

Holdings,

Inc.

(a)

25,454‌

56,253‌

Y-mAbs

Therapeutics,

Inc.

(a)

9,130‌

148,454‌

$

6,267,896‌

Software

-

0

.03

%

Outset

Medical,

Inc.

(a)

5,920‌

13,142‌

Transportation

-

0

.25

%

CryoPort,

Inc.

(a)

6,307‌

111,634‌

TOTAL

COMMON

STOCKS

a

$

44,531,700‌

INVESTMENT

COMPANIES

-

2

.72

%

Shares

Held

Value

Money

Market

Funds

-

2

.72

%

-

—

Principal

Government

Money

Market

Fund,

Class

R-6

5.22%

(d),(e),(f)

1,121,063‌

$

1,121,063‌

State

Street

Institutional

U.S.

Government

Money

Market

Fund,

Premier

Class

5.26%

(d)

91,027‌

91,027‌

TOTAL

INVESTMENT

COMPANIES

a

$

1,212,090‌

Total

Investments

$

45,743,790‌

Other

Assets

and

Liabilities

-

(2.51%)

(

1,119,149‌

)

TOTAL

NET

ASSETS

-

100.00%

$

44,624,641‌

(a)

Non-income

producing

security.

(b)

Security

or

a

portion

of

the

security

was

on

loan.

At

the

end

of

the

period,

the

value

of

these

securities

totaled

$1,020,394

or

2.29%

of

net

assets.

(c)

The

value

of

these

investments

was

determined

using

significant

unobservable

inputs,

in

good

faith

by

the

Advisor,

under

procedures

established

and

periodically

reviewed

by

the

Board

of

Trustees.

(d)

1-day

yield

shown

as

of

period

end.

(e)

Affiliated

Security.

Security

is

either

an

affiliate

(and

registered

under

the

Investment

Company

Act

of

1940)

or

an

affiliate

as

defined

by

the

Investment

Company

Act

of

1940

(controls

5.00%

or

more

of

the

outstanding

voting

shares

of

the

security).

Please

see

Affiliated

Securities

sub-schedule

for

transactional

information.

(f)

Security

or

a

portion

of

the

security

was

received

as

collateral

for

securities

lending.

At

the

end

of

the

period,

the

value

of

these

securities

totaled

$1,121,063

or

2.51%

of

net

assets.

Portfolio

Summary

Sector

Percent

Consumer,

Non-cyclical

99.41%

Money

Market

Funds

2.72%

Industrial

0.25%

Basic

Materials

0.10%

Technology

0.03%

Other

Assets

and

Liabilities

(2.51)%

TOTAL

NET

ASSETS

100.00%

8

Schedule

of

Investments

Principal

Healthcare

Innovators

ETF

March

31,

2024

(unaudited)

See

accompanying

notes.

Affiliated

Securities

June

30,

2023

Value

Purchases

Cost

Sales

Proceeds

March

31,

2024

Value

Principal

Government

Money

Market

Fund,

Class

R-6

5.22%

$

1,429,219‌

$

13,490,886‌

$

13,799,042‌

$

1,121,063‌

$

1,429,219‌

$

13,490,886‌

$

13,799,042‌

$

1,121,063‌

a

a

Income

(a)

Realized

Gain/(Loss)

on

Investments

Realized

Gain

from

Capital

Gain

Distributions

Change

in

Unrealized

Gain/(Loss)

Principal

Government

Money

Market

Fund,

Class

R-6

5.22%

$

—‌

$

—‌

$

—‌

$

—‌

$

—‌

$

—‌

$

—‌

$

—‌

(a)

Amount

excludes

earnings

from

securities

lending

collateral.

9

Schedule

of

Investments

Principal

Investment

Grade

Corporate

Active

ETF

March

31,

2024

(unaudited)

See

accompanying

notes.

BONDS

-

98

.65

%

Principal

Amount

Value

Aerospace

&

Defense

-

4

.75

%

—

—

BAE

Systems

PLC

5.00%,

03/26/2027

(a)

$

340,000‌

$

339,309‌

Boeing

Co.

2.20%,

02/04/2026

500,000‌

468,099‌

3.25%,

02/01/2028

654,000‌

601,699‌

5.71%,

05/01/2040

571,000‌

546,528‌

L3Harris

Technologies,

Inc.

5.05%,

06/01/2029

150,000‌

149,521‌

Lockheed

Martin

Corp.

5.70%,

11/15/2054

284,000‌

302,668‌

RTX

Corp.

4.13%,

11/16/2028

1,088,000‌

1,052,404‌

6.10%,

03/15/2034

203,000‌

216,963‌

$

3,677,191‌

Agriculture

-

0

.46

%

BAT

Capital

Corp.

5.83%,

02/20/2031

200,000‌

201,716‌

6.00%,

02/20/2034

155,000‌

156,945‌

$

358,661‌

Airlines

-

1

.28

%

Delta

Air

Lines,

Inc./SkyMiles

IP

Ltd.

4.75%,

10/20/2028

(a)

1,011,262‌

989,072‌

Auto

Manufacturers

-

2

.46

%

Cummins,

Inc.

5.45%,

02/20/2054

150,000‌

153,354‌

Ford

Motor

Credit

Co.

LLC

5.80%,

03/08/2029

375,000‌

376,492‌

Hyundai

Capital

America

5.25%,

01/08/2027

(a)

320,000‌

319,713‌

5.40%,

01/08/2031

(a)

254,000‌

255,009‌

6.50%,

01/16/2029

(a)

521,000‌

546,588‌

Toyota

Motor

Credit

Corp.

4.80%,

01/05/2034

258,000‌

253,815‌

$

1,904,971‌

Banks

-

22

.25

%

AIB

Group

PLC

(6-month

Secured

Overnight

Financing

Rate

+

1.91%),

5.87%,

03/28/2035

(a),(b)

425,000‌

426,191‌

Bank

of

America

Corp.

(6-month

Secured

Overnight

Financing

Rate

+

1.65%),

5.47%,

01/23/2035

(b)

2,677,000‌

2,694,449‌

Bank

of

New

York

Mellon

Corp.

,

Series

J

(6-month

Secured

Overnight

Financing

Rate

+

1.61%),

4.97%,

04/26/2034

(b)

714,000‌

700,900‌

BNP

Paribas

SA

(6-month

Secured

Overnight

Financing

Rate

+

1.59%),

5.50%,

05/20/2030

(a),(b)

390,000‌

390,852‌

Citigroup,

Inc.

(6-month

Secured

Overnight

Financing

Rate

+

1.54%),

5.61%,

09/29/2026

(b)

1,223,000‌

1,224,949‌

Deutsche

Bank

AG

(6-month

Secured

Overnight

Financing

Rate

+

1.59%),

5.71%,

02/08/2028

(b)

305,000‌

304,557‌

HSBC

Holdings

PLC

(6-month

Secured

Overnight

Financing

Rate

+

1.46%),

5.55%,

03/04/2030

(b)

420,000‌

422,510‌

JPMorgan

Chase

&

Co.

(6-month

Secured

Overnight

Financing

Rate

+

1.62%),

5.34%,

01/23/2035

(b)

177,000‌

177,692‌

BONDS

(continued)

Principal

Amount

Value

Banks

(continued)

JPMorgan

Chase

&

Co.

(continued)

(6-month

Secured

Overnight

Financing

Rate

+

1.81%),

6.25%,

10/23/2034

(b)

$

2,635,000‌

$

2,815,214‌

Mizuho

Financial

Group,

Inc.

(1-year

Treasury

Constant

Maturity

Rate

+

1.12%),

5.38%,

05/26/2030

(b)

250,000‌

251,136‌

Morgan

Stanley

(6-month

Secured

Overnight

Financing

Rate

+

1.73%),

5.47%,

01/18/2035

(b)

2,516,000‌

2,538,489‌

PNC

Financial

Services

Group,

Inc.

(6-month

Secured

Overnight

Financing

Rate

+

1.90%),

5.68%,

01/22/2035

(b)

846,000‌

853,706‌

(6-month

Secured

Overnight

Financing

Rate

+

2.28%),

6.88%,

10/20/2034

(b)

146,000‌

159,874‌

Royal

Bank

of

Canada

4.95%,

02/01/2029

248,000‌

248,593‌

Truist

Financial

Corp.

(6-month

Secured

Overnight

Financing

Rate

+

1.62%),

5.44%,

01/24/2030

(b)

152,000‌

151,823‌

(6-month

Secured

Overnight

Financing

Rate

+

1.92%),

5.71%,

01/24/2035

(b)

177,000‌

177,764‌

(6-month

Secured

Overnight

Financing

Rate

+

1.63%),

5.90%,

10/28/2026

(b)

340,000‌

341,687‌

(6-month

Secured

Overnight

Financing

Rate

+

2.45%),

7.16%,

10/30/2029

(b)

350,000‌

373,240‌

UBS

Group

AG

(1-year

Treasury

Constant

Maturity

Rate

+

1.75%),

4.75%,

05/12/2028

(a),(b)

1,228,000‌

1,203,267‌

(1-year

Treasury

Constant

Maturity

Rate

+

1.77%),

5.70%,

02/08/2035

(a),(b)

205,000‌

206,037‌

Wells

Fargo

&

Co.

(6-month

Secured

Overnight

Financing

Rate

+

2.10%),

2.39%,

06/02/2028

(b)

1,722,000‌

1,576,154‌

$

17,239,084‌

Beverages

-

2

.70

%

Anheuser-Busch

InBev

Worldwide,

Inc.

3.50%,

06/01/2030

759,000‌

706,989‌

4.38%,

04/15/2038

822,000‌

763,933‌

Constellation

Brands,

Inc.

4.75%,

05/09/2032

632,000‌

617,409‌

$

2,088,331‌

Biotechnology

-

0

.85

%

Amgen,

Inc.

5.60%,

03/02/2043

648,000‌

659,291‌

Chemicals

-

0

.23

%

International

Flavors

&

Fragrances,

Inc.

1.83%,

10/15/2027

(a)

200,000‌

177,343‌

Commercial

Services

-

1

.10

%

CoStar

Group,

Inc.

2.80%,

07/15/2030

(a)

1,001,000‌

853,317‌

Computers

-

0

.72

%

Apple,

Inc.

3.95%,

08/08/2052

657,000‌

553,733‌

Diversified

Financial

Services

-

1

.43

%

AerCap

Ireland

Capital

DAC/AerCap

Global

Aviation

Trust

3.00%,

10/29/2028

501,000‌

453,315‌

10

Schedule

of

Investments

Principal

Investment

Grade

Corporate

Active

ETF

March

31,

2024

(unaudited)

See

accompanying

notes.

BONDS

(continued)

Principal

Amount

Value

Diversified

Financial

Services

(continued)

AerCap

Ireland

Capital

DAC/AerCap

Global

Aviation

Trust

(continued)

3.85%,

10/29/2041

$

790‌

$

626‌

Blackstone

Holdings

Finance

Co.

LLC

2.85%,

08/05/2051

(a)

562,342‌

352,164‌

Lseg

U.S.

Fin

Corp.

5.30%,

03/28/2034

(a)

300,000‌

301,892‌

$

1,107,997‌

Electric

-

9

.43

%

Alliant

Energy

Finance

LLC

5.95%,

03/30/2029

(a)

117,000‌

120,502‌

Commonwealth

Edison

Co.

4.00%,

03/01/2049

564,000‌

449,644‌

Consolidated

Edison

Co.

of

New

York,

Inc.

5.90%,

11/15/2053

126,000‌

134,475‌

Duke

Energy

Carolinas

LLC

3.75%,

06/01/2045

564,000‌

439,497‌

Duke

Energy

Florida

LLC

6.20%,

11/15/2053

162,000‌

178,603‌

Entergy

Louisiana

LLC

4.95%,

01/15/2045

564,000‌

519,779‌

FirstEnergy

Corp.

,

Series

C

5.10%,

07/15/2047

424,000‌

372,212‌

Florida

Power

&

Light

Co.

3.95%,

03/01/2048

424,000‌

347,562‌

Indianapolis

Power

&

Light

Co.

5.70%,

04/01/2054

(a)

205,000‌

205,543‌

ITC

Holdings

Corp.

3.65%,

06/15/2024

596,000‌

592,959‌

Kentucky

Utilities

Co.

4.38%,

10/01/2045

615,000‌

528,727‌

MidAmerican

Energy

Co.

4.40%,

10/15/2044

564,000‌

490,939‌

Monongahela

Power

Co.

3.55%,

05/15/2027

(a)

440,000‌

418,511‌

National

Rural

Utilities

Cooperative

Finance

Corp.

5.00%,

02/07/2031

265,000‌

263,111‌

Northern

States

Power

Co.

5.10%,

05/15/2053

307,000‌

295,764‌

NRG

Energy,

Inc.

2.00%,

12/02/2025

(a)

570,000‌

534,964‌

Pacific

Gas

&

Electric

Co.

2.95%,

03/01/2026

1,084,000‌

1,034,906‌

5.55%,

05/15/2029

375,000‌

378,274‌

$

7,305,972‌

Engineering

&

Construction

-

0

.24

%

CIMIC

Finance

USA

Pty.

Ltd.

7.00%,

03/25/2034

(a),(c)

180,000‌

184,824‌

Entertainment

-

1

.26

%

Warnermedia

Holdings,

Inc.

4.28%,

03/15/2032

1,090,000‌

973,630‌

Environmental

Control

-

1

.51

%

Waste

Connections,

Inc.

4.20%,

01/15/2033

793,000‌

745,355‌

Waste

Management,

Inc.

4.63%,

02/15/2030

424,000‌

421,990‌

$

1,167,345‌

Food

-

0

.91

%

JBS

USA

LUX

SA/JBS

USA

Food

Co./JBS

USA

Finance,

Inc.

4.38%,

02/02/2052

482,400‌

350,319‌

Mars,

Inc.

2.38%,

07/16/2040

(a)

503,000‌

350,618‌

Sysco

Corp.

3.15%,

12/14/2051

736‌

504‌

$

701,441‌

BONDS

(continued)

Principal

Amount

Value

Gas

-

1

.77

%

NiSource,

Inc.

0.95%,

08/15/2025

$

1,377,000‌

$

1,295,836‌

5.25%,

03/30/2028

78,000‌

78,536‌

$

1,374,372‌

Healthcare

-

Products

-

1

.31

%

Boston

Scientific

Corp.

2.65%,

06/01/2030

1,151,000‌

1,013,741‌

Healthcare

-

Services

-

3

.37

%

Centene

Corp.

2.45%,

07/15/2028

1,233,000‌

1,093,318‌

HCA,

Inc.

5.45%,

04/01/2031

275,000‌

276,434‌

6.00%,

04/01/2054

324,000‌

328,854‌

UnitedHealth

Group,

Inc.

2.75%,

05/15/2040

580,000‌

426,792‌

5.38%,

04/15/2054

255,000‌

259,348‌

5.88%,

02/15/2053

212,000‌

229,364‌

$

2,614,110‌

Insurance

-

6

.19

%

AIA

Group

Ltd.

5.38%,

04/05/2034

(a)

200,000‌

199,802‌

Aon

North

America,

Inc.

5.45%,

03/01/2034

175,000‌

177,020‌

5.75%,

03/01/2054

250,000‌

256,301‌

Arthur

J

Gallagher

&

Co.

2.40%,

11/09/2031

709,000‌

581,313‌

6.75%,

02/15/2054

637,000‌

723,208‌

Athene

Holding

Ltd.

6.25%,

04/01/2054

325,000‌

329,837‌

Chubb

INA

Holdings,

Inc.

3.35%,

05/03/2026

579,000‌

559,304‌

Corebridge

Financial,

Inc.

5.75%,

01/15/2034

450,000‌

459,084‌

Everest

Reinsurance

Holdings,

Inc.

3.13%,

10/15/2052

509,000‌

329,222‌

MetLife,

Inc.

5.00%,

07/15/2052

281,000‌

264,538‌

New

York

Life

Insurance

Co.

3.75%,

05/15/2050

(a)

440,000‌

338,247‌

SiriusPoint

Ltd.

7.00%,

04/05/2029

175,000‌

174,975‌

Swiss

RE

Subordinated

Finance

PLC

(3-month

Term

Secured

Overnight

Financing

Rate

+

1.81%),

5.70%,

04/05/2035

(a),(b)

400,000‌

399,334‌

$

4,792,185‌

Internet

-

1

.00

%

Netflix,

Inc.

5.88%,

11/15/2028

747,000‌

776,527‌

Media

-

1

.32

%

Charter

Communications

Operating

LLC/Charter

Communications

Operating

Capital

4.80%,

03/01/2050

370,000‌

273,878‌

Comcast

Corp.

3.97%,

11/01/2047

652,000‌

524,077‌

Paramount

Global

4.20%,

05/19/2032

274,000‌

227,626‌

$

1,025,581‌

Mining

-

1

.87

%

Glencore

Funding

LLC

5.37%,

04/04/2029

(a)

875,000‌

876,735‌

6.13%,

10/06/2028

(a)

556,000‌

574,553‌

$

1,451,288‌

Oil

&

Gas

-

1

.94

%

BP

Capital

Markets

America,

Inc.

4.70%,

04/10/2029

254,000‌

253,363‌

Marathon

Oil

Corp.

4.40%,

07/15/2027

500,000‌

485,871‌

5.70%,

04/01/2034

175,000‌

174,991‌

11

Schedule

of

Investments

Principal

Investment

Grade

Corporate

Active

ETF

March

31,

2024

(unaudited)

See

accompanying

notes.

BONDS

(continued)

Principal

Amount

Value

Oil

&

Gas

(continued)

Marathon

Oil

Corp.

(continued)

6.60%,

10/01/2037

$

255,000‌

$

268,281‌

Occidental

Petroleum

Corp.

6.60%,

03/15/2046

300,000‌

323,318‌

$

1,505,824‌

Packaging

&

Containers

-

0

.95

%

Packaging

Corp.

of

America

5.70%,

12/01/2033

521,000‌

538,097‌

Smurfit

Kappa

Treasury

ULC

5.20%,

01/15/2030

(a)

200,000‌

199,605‌

$

737,702‌

Pharmaceuticals

-

6

.90

%

AbbVie,

Inc.

3.20%,

11/21/2029

582,000‌

536,311‌

4.05%,

11/21/2039

862,000‌

767,524‌

4.95%,

03/15/2031

770,000‌

775,495‌

5.40%,

03/15/2054

115,000‌

118,369‌

Becton

Dickinson

&

Co.

3.70%,

06/06/2027

1,510,000‌

1,450,718‌

Bristol-Myers

Squibb

Co.

4.13%,

06/15/2039

424,000‌

375,723‌

Pfizer

Investment

Enterprises

Pte.

Ltd.

5.11%,

05/19/2043

295,000‌

288,467‌

Zoetis,

Inc.

3.90%,

08/20/2028

1,074,000‌

1,033,404‌

$

5,346,011‌

Pipelines

-

5

.39

%

Cheniere

Energy,

Inc.

5.65%,

04/15/2034

(a)

170,000‌

171,214‌

Energy

Transfer

LP

3.75%,

05/15/2030

729,000‌

671,922‌

5.15%,

03/15/2045

497,000‌

451,591‌

5.95%,

05/15/2054

140,000‌

139,712‌

Enterprise

Products

Operating

LLC

3.13%,

07/31/2029

1,166,000‌

1,075,519‌

Kinder

Morgan,

Inc.

5.40%,

02/01/2034

600,000‌

597,593‌

MPLX

LP

4.88%,

12/01/2024

571,000‌

567,907‌

Sabine

Pass

Liquefaction

LLC

5.00%,

03/15/2027

502,000‌

500,532‌

$

4,175,990‌

REITs

-

2

.73

%

Crown

Castle,

Inc.

5.80%,

03/01/2034

521,000‌

532,959‌

Invitation

Homes

Operating

Partnership

LP

2.00%,

08/15/2031

428,000‌

340,085‌

Kimco

Realty

OP

LLC

3.20%,

04/01/2032

798,000‌

687,655‌

Realty

Income

Corp.

3.10%,

12/15/2029

70‌

63‌

3.20%,

02/15/2031

624,000‌

553,075‌

$

2,113,837‌

Semiconductors

-

2

.10

%

Broadcom,

Inc.

4.11%,

09/15/2028

511,000‌

493,703‌

Intel

Corp.

5.00%,

02/21/2031

185,000‌

185,189‌

5.15%,

02/21/2034

175,000‌

175,399‌

BONDS

(continued)

Principal

Amount

Value

Semiconductors

(continued)

Marvell

Technology,

Inc.

5.95%,

09/15/2033

$

315,000‌

$

326,439‌

Micron

Technology,

Inc.

5.30%,

01/15/2031

193,000‌

194,116‌

6.75%,

11/01/2029

234,000‌

251,167‌

$

1,626,013‌

Software

-

4

.84

%

Fiserv,

Inc.

4.40%,

07/01/2049

469,000‌

397,895‌

Intuit,

Inc.

5.50%,

09/15/2053

244,000‌

253,288‌

Oracle

Corp.

2.80%,

04/01/2027

424,000‌

397,647‌

4.00%,

07/15/2046

424,000‌

334,014‌

6.15%,

11/09/2029

219,000‌

230,812‌

Take-Two

Interactive

Software,

Inc.

4.00%,

04/14/2032

654,000‌

604,103‌

4.95%,

03/28/2028

254,000‌

253,024‌

VMware

LLC

4.65%,

05/15/2027

1,299,000‌

1,276,942‌

$

3,747,725‌

Telecommunications

-

4

.09

%

AT&T,

Inc.

3.50%,

09/15/2053

1,741,000‌

1,228,314‌

T-Mobile

USA,

Inc.

3.38%,

04/15/2029

1,381,000‌

1,277,191‌

3.50%,

04/15/2031

500,000‌

451,539‌

6.00%,

06/15/2054

201,000‌

214,838‌

$

3,171,882‌

Transportation

-

0

.46

%

Norfolk

Southern

Corp.

5.35%,

08/01/2054

360,000‌

357,383‌

Water

-

0

.84

%

Essential

Utilities,

Inc.

2.40%,

05/01/2031

784,000‌

649,405‌

TOTAL

BONDS

a

$

76,421,779‌

INVESTMENT

COMPANIES

-

1

.34

%

Shares

Held

Value

Money

Market

Funds

-

1

.34

%

-

—

Principal

Government

Money

Market

Fund,

Class

R-6

5.22%

(d),(e),(f)

141,750‌

$

141,750‌

State

Street

Institutional

U.S.

Government

Money

Market

Fund,

Premier

Class

5.26%

(d)

899,401‌

899,401‌

TOTAL

INVESTMENT

COMPANIES

a

$

1,041,151‌

Total

Investments

$

77,462,930‌

Other

Assets

and

Liabilities

-

0.01%

6,877‌

TOTAL

NET

ASSETS

-

100.00%

$

77,469,807‌

(a)

Security

exempt

from

registration

under

Rule

144A

of

the

Securities

Act

of

1933.

These

securities

may

be

resold

in

transactions

exempt

from

registration,

normally

to

qualified

institutional

buyers.

At

the

end

of

the

period,

the

value

of

these

securities

totaled

$10,935,206

or

14.12%

of

net

assets.

(b)

Rate

shown

is

as

of

period

end.

The

rate

may

be

a

variable

or

floating

rate

or

a

fixed

rate

which

may

convert

to

a

variable

or

floating

rate

in

the

future.

(c)

Security

or

a

portion

of

the

security

was

on

loan.

At

the

end

of

the

period,

the

value

of

these

securities

totaled

$138,481

or

0.18%

of

net

assets.

(d)

1-day

yield

shown

as

of

period

end.

(e)

Affiliated

Security.

Security

is

either

an

affiliate

(and

registered

under

the

Investment

Company

Act

of

1940)

or

an

affiliate

as

defined

by

the

Investment

Company

Act

of

1940

(controls

5.00%

or

more

of

the

outstanding

voting

shares

of

the

security).

Please

see

Affiliated

Securities

sub-schedule

for

transactional

information.

(f)

Security

or

a

portion

of

the

security

was

received

as

collateral

for

securities

lending.

At

the

end

of

the

period,

the

value

of

these

securities

totaled

$141,750

or

0.18%

of

net

assets.

12

Schedule

of

Investments

Principal

Investment

Grade

Corporate

Active

ETF

March

31,

2024

(unaudited)

See

accompanying

notes.

Portfolio

Summary

Sector

Percent

Financial

32.60%

Consumer,

Non-cyclical

17.60%

Utilities

12.04%

Industrial

7.91%

Technology

7.66%

Energy

7.33%

Communications

6.41%

Consumer,

Cyclical

5.00%

Basic

Materials

2.10%

Money

Market

Funds

1.34%

Other

Assets

and

Liabilities

0.01%

TOTAL

NET

ASSETS

100.00%

Affiliated

Securities

June

30,

2023

Value

Purchases

Cost

Sales

Proceeds

March

31,

2024

Value

Principal

Government

Money

Market

Fund,

Class

R-6

5.22%

$

384,880‌

$

7,213,745‌

$

7,456,875‌

$

141,750‌

$

384,880‌

$

7,213,745‌

$

7,456,875‌

$

141,750‌

a

a

Income

(a)

Realized

Gain/(Loss)

on

Investments

Realized

Gain

from

Capital

Gain

Distributions

Change

in

Unrealized

Gain/(Loss)

Principal

Government

Money

Market

Fund,

Class

R-6

5.22%

$

—‌

$

—‌

$

—‌

$

—‌

$

—‌

$

—‌

$

—‌

$

—‌

(a)

Amount

excludes

earnings

from

securities

lending

collateral.

Futures

Contracts

Description

and

Expiration

Date

Type  

Contracts

Notional

Amount

Value

and

Unrealized

Appreciation/(Depreciation)

U.S.

5

Year

Note

CBT;

June

2024

Short

5‌

$

535,078‌

$

615‌

U.S.

10

Year

Note

CBT;

June

2024

Short

21‌

2,326,734‌

(

6,795‌

)

U.S.

10

Year

Ultra

Note

CBT;

June

2024

Short

24‌

2,750,625‌

1,794‌

U.S.

Long

Bond

CBT;

June

2024

Long

16‌

1,927,000‌

13,995‌

U.S.

Ultra

Bond

CBT;

June

2024

Long

17‌

2,193,000‌

16,458‌

Total

$

26,067‌

13

Schedule

of

Investments

Principal

Quality

ETF

March

31,

2024

(unaudited)

See

accompanying

notes.

COMMON

STOCKS

-

99

.76

%

Shares

Held

Value

Auto

Parts

&

Equipment

-

1

.08

%

-

—

Aptiv

PLC

(a)

6,609‌

$

526,407‌

Building

Materials

-

3

.41

%

Martin

Marietta

Materials,

Inc.

892‌

547,634‌

Trane

Technologies

PLC

1,923‌

577,285‌

Vulcan

Materials

Co.

1,969‌

537,379‌

$

1,662,298‌

Chemicals

-

2

.27

%

Ecolab,

Inc.

2,426‌

560,164‌

PPG

Industries,

Inc.

3,788‌

548,881‌

$

1,109,045‌

Commercial

Services

-

4

.53

%

Corpay,

Inc.

(a)

1,724‌

531,923‌

Gartner,

Inc.

(a)

1,129‌

538,160‌

Global

Payments,

Inc.

4,032‌

538,917‌

PayPal

Holdings,

Inc.

(a)

8,930‌

598,221‌

$

2,207,221‌

Computers

-

9

.25

%

Accenture

PLC,

Class

A

1,993‌

690,794‌

Apple,

Inc.

12,094‌

2,073,879‌

Hewlett

Packard

Enterprise

Co.

30,493‌

540,641‌

International

Business

Machines

Corp.

3,583‌

684,210‌

NetApp,

Inc.

4,982‌

522,960‌

$

4,512,484‌

Distribution

&

Wholesale

-

2

.27

%

Copart,

Inc.

(a)

9,630‌

557,769‌

WW

Grainger,

Inc.

539‌

548,325‌

$

1,106,094‌

Diversified

Financial

Services

-

1

.04

%

Cboe

Global

Markets,

Inc.

2,766‌

508,197‌

Electrical

Components

&

Equipment

-

1

.10

%

AMETEK,

Inc.

2,936‌

536,994‌

Electronics

-

3

.29

%

Allegion

PLC

3,827‌

515,535‌

Jabil,

Inc.

4,090‌

547,856‌

Keysight

Technologies,

Inc.

(a)

3,443‌

538,416‌

$

1,601,807‌

Environmental

Control

-

1

.11

%

Republic

Services,

Inc.

2,836‌

542,924‌

Food

-

1

.09

%

Sysco

Corp.

6,567‌

533,109‌

Hand

&

Machine

Tools

-

1

.06

%

Snap-on,

Inc.

1,739‌

515,127‌

Healthcare

-

Products

-

7

.39

%

Agilent

Technologies,

Inc.

3,621‌

526,892‌

Boston

Scientific

Corp.

(a)

8,962‌

613,807‌

Edwards

Lifesciences

Corp.

(a)

5,939‌

567,531‌

Stryker

Corp.

1,756‌

628,420‌

Thermo

Fisher

Scientific,

Inc.

1,269‌

737,555‌

West

Pharmaceutical

Services,

Inc.

1,336‌

528,669‌

$

3,602,874‌

Healthcare

-

Services

-

1

.10

%

IQVIA

Holdings,

Inc.

(a)

2,128‌

538,150‌

Home

Builders

-

2

.34

%

DR

Horton,

Inc.

3,541‌

582,672‌

PulteGroup,

Inc.

4,626‌

557,988‌

$

1,140,660‌

Household

Products

&

Wares

-

2

.19

%

Church

&

Dwight

Co.,

Inc.

4,933‌

514,561‌

Kimberly-Clark

Corp.

4,280‌

553,618‌

$

1,068,179‌

Insurance

-

0

.23

%

Berkshire

Hathaway,

Inc.,

Class

B

(a)

264‌

111,017‌

COMMON

STOCKS

(continued)

Shares

Held

Value

Internet

-

9

.15

%

Alphabet,

Inc.,

Class

A

(a)

1,494‌

$

225,490‌

Alphabet,

Inc.,

Class

C

(a)

5,543‌

843,977‌

Amazon.com,

Inc.

(a)

6,005‌

1,083,182‌

CDW

Corp.

2,130‌

544,811‌

F5,

Inc.

(a)

2,653‌

502,982‌

Meta

Platforms,

Inc.,

Class

A

981‌

476,354‌

Netflix,

Inc.

(a)

1,296‌

787,100‌

$

4,463,896‌

Machinery

-

Diversified

-

4

.30

%

Dover

Corp.

2,925‌

518,281‌

IDEX

Corp.

2,110‌

514,882‌

Nordson

Corp.

1,909‌

524,097‌

Rockwell

Automation,

Inc.

1,857‌

541,000‌

$

2,098,260‌

Media

-

0

.99

%

FactSet

Research

Systems,

Inc.

1,063‌

483,017‌

Miscellaneous

Manufacturers

-

3

.56

%

A

O

Smith

Corp.

5,720‌

511,711‌

Eaton

Corp.

PLC

2,091‌

653,814‌

Illinois

Tool

Works,

Inc.

2,124‌

569,933‌

$

1,735,458‌

Oil

&

Gas

Services

-

1

.21

%

Schlumberger

Ltd.

10,778‌

590,742‌

Pharmaceuticals

-

1

.15

%

Zoetis,

Inc.

3,325‌

562,623‌

Retail

-

3

.43

%

Chipotle

Mexican

Grill,

Inc.

(a)

207‌

601,701‌

O'Reilly

Automotive,

Inc.

(a)

503‌

567,827‌

Ulta

Beauty,

Inc.

(a)

961‌

502,488‌

$

1,672,016‌

Semiconductors

-

13

.89

%

Advanced

Micro

Devices,

Inc.

(a)

4,363‌

787,478‌

Applied

Materials,

Inc.

3,375‌

696,026‌

Broadcom,

Inc.

884‌

1,171,662‌

KLA

Corp.

868‌

606,359‌

Microchip

Technology,

Inc.

6,086‌

545,975‌

Monolithic

Power

Systems,

Inc.

761‌

515,517‌

NVIDIA

Corp.

1,929‌

1,742,967‌

QUALCOMM,

Inc.

4,170‌

705,981‌

$

6,771,965‌

Software

-

16

.11

%

Broadridge

Financial

Solutions,

Inc.

2,559‌

524,237‌

Cadence

Design

Systems,

Inc.

(a)

1,946‌

605,751‌

Fiserv,

Inc.

(a)

3,915‌

625,695‌

Intuit,

Inc.

1,088‌

707,200‌

Microsoft

Corp.

9,426‌

3,965,707‌

Salesforce,

Inc.

2,747‌

827,341‌

Synopsys,

Inc.

(a)

1,053‌

601,790‌

$

7,857,721‌

Telecommunications

-

1

.22

%

Arista

Networks,

Inc.

(a)

2,046‌

593,299‌

TOTAL

COMMON

STOCKS

a

$

48,651,584‌

INVESTMENT

COMPANIES

-

0

.19

%

Shares

Held

Value

Money

Market

Funds

-

0

.19

%

-

—

State

Street

Institutional

U.S.

Government

Money

Market

Fund,

Premier

Class

5.26%

(b)

94,330‌

$

94,330‌

TOTAL

INVESTMENT

COMPANIES

a

$

94,330‌

Total

Investments

$

48,745,914‌

Other

Assets

and

Liabilities

-

0.05%

24,340‌

TOTAL

NET

ASSETS

-

100.00%

$

48,770,254‌

(a)

Non-income

producing

security.

(b)

1-day

yield

shown

as

of

period

end.

14

Schedule

of

Investments

Principal

Quality

ETF

March

31,

2024

(unaudited)

See

accompanying

notes.

Portfolio

Summary

Sector

Percent

Technology

39.25%

Industrial

17.83%

Consumer,

Non-cyclical

17.45%

Communications

11.36%

Consumer,

Cyclical

9.12%

Basic

Materials

2.27%

Financial

1.27%

Energy

1.21%

Money

Market

Funds

0.19%

Other

Assets

and

Liabilities

0.05%

TOTAL

NET

ASSETS

100.00%

15

Schedule

of

Investments

Principal

Real

Estate

Active

Opportunities

ETF

March

31,

2024

(unaudited)

See

accompanying

notes.

COMMON

STOCKS

-

98

.21

%

Shares

Held

Value

Entertainment

-

1

.86

%

-

—

Marriott

Vacations

Worldwide

Corp.

1,628‌

$

175,384‌

REITs

-

96

.35

%

Alexandria

Real

Estate

Equities,

Inc.

2,431‌

313,380‌

American

Healthcare

REIT,

Inc.

13,517‌

199,376‌

American

Homes

4

Rent,

Class

A

12,056‌

443,420‌

American

Tower

Corp.

3,266‌

645,329‌

Americold

Realty

Trust,

Inc.

15,240‌

379,781‌

Crown

Castle,

Inc.

2,514‌

266,057‌

DiamondRock

Hospitality

Co.

20,501‌

197,015‌

Digital

Realty

Trust,

Inc.

2,452‌

353,186‌

Equinix,

Inc.

602‌

496,849‌

Extra

Space

Storage,

Inc.

4,515‌

663,705‌

Gaming

&

Leisure

Properties,

Inc.

8,890‌

409,562‌

Invitation

Homes,

Inc.

18,087‌

644,078‌

National

Health

Investors,

Inc.

5,018‌

315,281‌

Rexford

Industrial

Realty,

Inc.

12,023‌

604,757‌

Sabra

Health

Care

REIT,

Inc.

26,064‌

384,965‌

SBA

Communications

Corp.

1,820‌

394,394‌

Sun

Communities,

Inc.

3,694‌

474,974‌

Terreno

Realty

Corp.

6,363‌

422,503‌

COMMON

STOCKS

(continued)

Shares

Held

Value

REITs

(continued)

Ventas,

Inc.

15,293‌

$

665,857‌

VICI

Properties,

Inc.

13,237‌

394,330‌

Welltower,

Inc.

4,586‌

428,516‌

$

9,097,315‌

TOTAL

COMMON

STOCKS

a

$

9,272,699‌

INVESTMENT

COMPANIES

-

1

.23

%

Shares

Held

Value

Money

Market

Funds

-

1

.23

%

-

—

State

Street

Institutional

U.S.

Government

Money

Market

Fund,

Premier

Class

5.26%

(a)

115,696‌

$

115,696‌

TOTAL

INVESTMENT

COMPANIES

a

$

115,696‌

Total

Investments

$

9,388,395‌

Other

Assets

and

Liabilities

-

0.56%

53,285‌

TOTAL

NET

ASSETS

-

100.00%

$

9,441,680‌

(a)

1-day

yield

shown

as

of

period

end.

Portfolio

Summary

Sector

Percent

Financial

96.35%

Consumer,

Cyclical

1.86%

Money

Market

Funds

1.23%

Other

Assets

and

Liabilities

0.56%

TOTAL

NET

ASSETS

100.00%

16

Schedule

of

Investments

Principal

Spectrum

Preferred

Securities

Active

ETF

March

31,

2024

(unaudited)

See

accompanying

notes.

BONDS

-

98

.56

%

Principal

Amount

Value

Banks

-

50

.20

%

—

—

Bank

of

America

Corp.

,

Series

RR

(5-year

Treasury

Constant

Maturity

Rate

+

2.76%),

4.38%,

01/27/2027

(a),(b)

$

16,559,000‌

$

15,523,111‌

Bank

of

America

Corp.

,

Series

TT

(5-year

Treasury

Constant

Maturity

Rate

+

3.23%),

6.13%,

04/27/2027

(a),(b)

12,025,000‌

12,057,840‌

Bank

of

America

Corp.

,

Series

X

(3-month

Term

Secured

Overnight

Financing

Rate

+

3.97%),

6.25%,

09/05/2024

(a),(b)

3,711,000‌

3,715,223‌

Bank

of

Montreal

(5-year

Treasury

Constant

Maturity

Rate

+

2.98%),

4.80%,

08/25/2024

(a),(b)

4,112,000‌

4,018,334‌

(5-year

Treasury

Constant

Maturity

Rate

+

3.45%),

7.70%,

05/26/2084

(b)

800,000‌

809,401‌

Bank

of

New

York

Mellon

Corp.

,

Series

F

(3-month

Term

Secured

Overnight

Financing

Rate

+

3.39%),

4.63%,

09/20/2026

(a),(b)

1,504,000‌

1,420,459‌

Bank

of

New

York

Mellon

Corp.

,

Series

G

(5-year

Treasury

Constant

Maturity

Rate

+

4.36%),

4.70%,

09/20/2025

(a),(b)

7,900,000‌

7,751,743‌

Bank

of

New

York

Mellon

Corp.

,

Series

H

(5-year

Treasury

Constant

Maturity

Rate

+

3.35%),

3.70%,

03/20/2026

(a),(b)

16,671,000‌

15,724,746‌

Bank

of

New

York

Mellon

Corp.

,

Series

I

(5-year

Treasury

Constant

Maturity

Rate

+

2.63%),

3.75%,

12/20/2026

(a),(b)

10,185,000‌

9,335,572‌

Bank

of

Nova

Scotia

(5-year

Treasury

Constant

Maturity

Rate

+

4.55%),

4.90%,

06/04/2025

(a),(b)

9,915,000‌

9,756,588‌

(5-year

Treasury

Constant

Maturity

Rate

+

4.38%),

8.63%,

10/27/2082

(b)

18,569,000‌

19,334,061‌

Citigroup,

Inc.

,

Series

V

(6-month

Secured

Overnight

Financing

Rate

+

3.23%),

4.70%,

01/30/2025

(a),(b)

3,000,000‌

2,926,477‌

Citigroup,

Inc.

,

Series

W

(5-year

Treasury

Constant

Maturity

Rate

+

3.60%),

4.00%,

12/10/2025

(a),(b)

15,226,000‌

14,597,871‌

Citigroup,

Inc.

,

Series

X

(5-year

Treasury

Constant

Maturity

Rate

+

3.42%),

3.88%,

02/18/2026

(a),(b)

11,262,000‌

10,628,771‌

Citigroup,

Inc.

,

Series

Z

(5-year

Treasury

Constant

Maturity

Rate

+

3.20%),

7.38%,

05/15/2028

(a),(b)

7,530,000‌

7,829,408‌

Citizens

Financial

Group,

Inc.

,

Series

F

(5-year

Treasury

Constant

Maturity

Rate

+

5.31%),

5.65%,

10/06/2025

(a),(b)

16,405,000‌

16,029,179‌

Citizens

Financial

Group,

Inc.

,

Series

G

(5-year

Treasury

Constant

Maturity

Rate

+

3.22%),

4.00%,

10/06/2026

(a),(b)

7,104,000‌

6,115,861‌

BONDS

(continued)

Principal

Amount

Value

Banks

(continued)

Goldman

Sachs

Group,

Inc.

,

Series

Q

(5-year

Treasury

Constant

Maturity

Rate

+

3.62%),

5.50%,

08/10/2024

(a),(b)

$

8,268,000‌

$

8,197,274‌

Goldman

Sachs

Group,

Inc.

,

Series

T

(5-year

Treasury

Constant

Maturity

Rate

+

2.97%),

3.80%,

05/10/2026

(a),(b)

1,268,000‌

1,181,056‌

Goldman

Sachs

Group,

Inc.

,

Series

U

(5-year

Treasury

Constant

Maturity

Rate

+

2.92%),

3.65%,

08/10/2026

(a),(b)

2,261,000‌

2,065,112‌

Goldman

Sachs

Group,

Inc.

,

Series

V

(5-year

Treasury

Constant

Maturity

Rate

+

2.95%),

4.13%,

11/10/2026

(a),(b)

8,563,000‌

7,947,997‌

HSBC

Capital

Funding

Dollar

1

LP

,

Series

2

(3-month

USD

LIBOR

+

4.98%),

10.18%,

06/30/2030

(a),(b)

6,049,000‌

7,592,130‌

Huntington

Bancshares,

Inc.

,

Series

F

(10-year

Treasury

Constant

Maturity

Rate

+

4.95%),

5.63%,

07/15/2030

(a),(b)

13,567,000‌

12,340,230‌

Huntington

Bancshares,

Inc.

,

Series

G

(7-year

Treasury

Constant

Maturity

Rate

+

4.05%),

4.45%,

10/15/2027

(a),(b)

5,080,000‌

4,603,481‌

JPMorgan

Chase

&

Co.

(5-year

Treasury

Constant

Maturity

Rate

+

2.74%),

6.88%,

06/01/2029

(a),(b)

4,400,000‌

4,552,998‌

JPMorgan

Chase

&

Co.

,

Series

KK

(5-year

Treasury

Constant

Maturity

Rate

+

2.85%),

3.65%,

06/01/2026

(a),(b)

18,288,000‌

17,368,794‌

JPMorgan

Chase

&

Co.

,

Series

S

(3-month

Term

Secured

Overnight

Financing

Rate

+

4.04%),

9.35%,

05/01/2024

(a)

9,791,000‌

9,802,132‌

KeyCorp

Capital

I

(3-month

Term

Secured

Overnight

Financing

Rate

+

1.00%),

6.30%,

07/01/2028

7,704,000‌

6,847,186‌

KeyCorp

Capital

III

7.75%,

07/15/2029

9,000,000‌

9,017,964‌

M&T

Bank

Corp.

,

Series

G

(5-year

Treasury

Constant

Maturity

Rate

+

3.17%),

5.00%,

08/01/2024

(a),(b)

5,000,000‌

4,805,382‌

M&T

Bank

Corp.

,

Series

I

(5-year

Treasury

Constant

Maturity

Rate

+

2.68%),

3.50%,

09/01/2026

(a),(b)

19,608,000‌

15,039,550‌

Northern

Trust

Corp.

,

Series

D

(3-month

Term

Secured

Overnight

Financing

Rate

+

3.46%),

4.60%,

10/01/2026

(a),(b)

2,899,000‌

2,782,339‌

PNC

Financial

Services

Group,

Inc.

,

Series

T

(5-year

Treasury

Constant

Maturity

Rate

+

2.60%),

3.40%,

09/15/2026

(a),(b)

7,346,000‌

6,420,696‌

PNC

Financial

Services

Group,

Inc.

,

Series

U

(5-year

Treasury

Constant

Maturity

Rate

+

3.00%),

6.00%,

05/15/2027

(a),(b)

1,800,000‌

1,759,587‌

PNC

Financial

Services

Group,

Inc.

,

Series

V

(5-year

Treasury

Constant

Maturity

Rate

+

3.24%),

6.20%,

09/15/2027

(a),(b)

13,908,000‌

13,871,788‌

17

Schedule

of

Investments

Principal

Spectrum

Preferred

Securities

Active

ETF

March

31,

2024

(unaudited)

See

accompanying

notes.

BONDS

(continued)

Principal

Amount

Value

Banks

(continued)

PNC

Financial

Services

Group,

Inc.

,

Series

W

(7-year

Treasury

Constant

Maturity

Rate

+

2.81%),

6.25%,

03/15/2030

(a),(b)

$

10,290,000‌

$

9,972,784‌

State

Street

Corp.

,

Series

I

(5-year

Treasury

Constant

Maturity

Rate

+

2.61%),

6.70%,

03/15/2029

(a),(b)

2,028,000‌

2,057,856‌

Toronto-Dominion

Bank

(5-year

Treasury

Constant

Maturity

Rate

+

4.07%),

8.13%,

10/31/2082

(b)

25,626,000‌

26,877,907‌

Truist

Financial

Corp.

(3-month

Term

Secured

Overnight

Financing

Rate

+

0.91%),

6.24%,

03/15/2028

1,250,000‌

1,179,007‌

Truist

Financial

Corp.

,

Series

A

(3-month

Term

Secured

Overnight

Financing

Rate

+

0.93%),

6.24%,

05/15/2027

4,800,000‌

4,562,399‌

Truist

Financial

Corp.

,

Series

L

(3-month

Term

Secured

Overnight

Financing

Rate

+

3.36%),

8.69%,

12/15/2024

(a),(c)

2,799,000‌

2,817,899‌

Truist

Financial

Corp.

,

Series

N

(5-year

Treasury

Constant

Maturity

Rate

+

3.00%),

4.80%,

09/01/2024

(a),(b)

10,894,000‌

10,544,463‌

Truist

Financial

Corp.

,

Series

P

(5-year

Treasury

Constant

Maturity

Rate

+

4.61%),

4.95%,

09/01/2025

(a),(b)

11,697,000‌

11,475,734‌

U.S.

Bancorp

,

Series

J

(3-month

Term

Secured

Overnight

Financing

Rate

+

3.18%),

5.30%,

04/15/2027

(a),(b),(c)

5,296,000‌

5,070,422‌

U.S.

Bancorp

,

Series

N

(5-year

Treasury

Constant

Maturity

Rate

+

2.54%),

3.70%,

01/15/2027

(a),(b)

21,525,000‌

18,668,851‌

Wells

Fargo

&

Co.

(5-year

Treasury

Constant

Maturity

Rate

+

3.61%),

7.63%,

09/15/2028

(a),(b)

9,710,000‌

10,377,155‌

Wells

Fargo

&

Co.

,

Series

BB

(5-year

Treasury

Constant

Maturity

Rate

+

3.45%),

3.90%,

03/15/2026

(a),(b)

31,418,000‌

29,891,911‌

$

427,266,729‌

Diversified

Financial

Services

-

12

.89

%

American

Express

Co.

,

Series

D

(5-year

Treasury

Constant

Maturity

Rate

+

2.85%),

3.55%,

09/15/2026

(a),(b)

33,567,000‌

31,069,840‌

Capital

One

Financial

Corp.

,

Series

M

(5-year

Treasury

Constant

Maturity

Rate

+

3.16%),

3.95%,

09/01/2026

(a),(b)

18,516,000‌

16,447,309‌

Charles

Schwab

Corp.

,

Series

G

(5-year

Treasury

Constant

Maturity

Rate

+

4.97%),

5.38%,

06/01/2025

(a),(b)

8,938,000‌

8,876,141‌

Charles

Schwab

Corp.

,

Series

I

(5-year

Treasury

Constant

Maturity

Rate

+

3.17%),

4.00%,

06/01/2026

(a),(b)

22,331,000‌

20,892,294‌

BONDS

(continued)

Principal

Amount

Value

Diversified

Financial

Services

(continued)

Charles

Schwab

Corp.

,

Series

K

(5-year

Treasury

Constant

Maturity

Rate

+

3.26%),

5.00%,

06/01/2027

(a),(b)

$

1,500,000‌

$

1,434,090‌

Discover

Financial

Services

,

Series

D

(5-year

Treasury

Constant

Maturity

Rate

+

5.78%),

6.13%,

06/23/2025

(a),(b)

16,441,000‌

16,474,934‌

Voya

Financial,

Inc.

,

Series

A

(5-year

Treasury

Constant

Maturity

Rate

+

3.36%),

7.76%,

09/15/2028

(a),(b)

13,990,000‌

14,506,875‌

$

109,701,483‌

Electric

-

13

.97

%

American

Electric

Power

Co.,

Inc.

(5-year

Treasury

Constant

Maturity

Rate

+

2.68%),

3.88%,

02/15/2062

(b)

11,007,000‌

9,891,371‌

CMS

Energy

Corp.

(5-year

Treasury

Constant

Maturity

Rate

+

4.12%),

4.75%,

06/01/2050

(b)

3,054,000‌

2,812,761‌

Dominion

Energy,

Inc.

(3-month

USD

LIBOR

+

3.06%),

5.75%,

10/01/2054

(b)

3,500,000‌

3,478,262‌

Dominion

Energy,

Inc.

,

Series

B

(5-year

Treasury

Constant

Maturity

Rate

+

2.99%),

4.65%,

12/15/2024

(a),(b)

14,234,000‌

13,932,582‌

Dominion

Energy,

Inc.

,

Series

C

(5-year

Treasury

Constant

Maturity

Rate

+

3.20%),

4.35%,

01/15/2027

(a),(b)

14,701,000‌

13,762,581‌

Duke

Energy

Corp.

(5-year

Treasury

Constant

Maturity

Rate

+

2.32%),

3.25%,

01/15/2082

(b)

13,234,000‌

11,760,207‌

(5-year

Treasury

Constant

Maturity

Rate

+

3.39%),

4.88%,

09/16/2024

(a),(b)

21,041,000‌

20,857,544‌

Emera,

Inc.

,

Series

16-A

(3-month

USD

LIBOR

+

5.44%),

6.75%,

06/15/2076

(b)

4,386,000‌

4,331,719‌

NextEra

Energy

Capital

Holdings,

Inc.

(5-year

Treasury

Constant

Maturity

Rate

+

2.55%),

3.80%,

03/15/2082

(b)

18,349,000‌

16,646,791‌

(5-year

Treasury

Constant

Maturity

Rate

+

2.36%),

6.70%,

09/01/2054

(b)

4,000,000‌

4,019,959‌

Southern

Co.

,

Series

B

(5-year

Treasury

Constant

Maturity

Rate

+

3.73%),

4.00%,

01/15/2051

(b)

18,095,000‌

17,395,853‌

$

118,889,630‌

Hand

&

Machine

Tools

-

0

.24

%

Stanley

Black

&

Decker,

Inc.

(5-year

Treasury

Constant

Maturity

Rate

+

2.66%),

4.00%,

03/15/2060

(b)

2,316,000‌

2,039,810‌

Insurance

-

13

.55

%

Allianz

SE

(5-year

Treasury

Constant

Maturity

Rate

+

3.23%),

6.35%,

09/06/2053

(b),(d)

5,000,000‌

5,248,405‌

Allstate

Corp.

,

Series

B

(3-month

Term

Secured

Overnight

Financing

Rate

+

3.20%),

8.51%,

08/15/2053

4,151,000‌

4,152,229‌

18

Schedule

of

Investments

Principal

Spectrum

Preferred

Securities

Active

ETF

March

31,

2024

(unaudited)

See

accompanying

notes.

BONDS

(continued)

Principal

Amount

Value

Insurance

(continued)

American

International

Group,

Inc.

,

Series

A-9

(3-month

USD

LIBOR

+

2.87%),

5.75%,

04/01/2048

(b)

$

3,176,000‌

$

3,118,290‌

Argentum

Netherlands

BV

for

Swiss

Re

Ltd.

(3-month

USD

LIBOR

+

3.78%),

5.63%,

08/15/2052

(b)

6,500,000‌

6,401,200‌

Argentum

Netherlands

BV

for

Zurich

Insurance

Co.

Ltd.

(5-year

Treasury

Constant

Maturity

Rate

+

3.27%),

5.13%,

06/01/2048

(b)

4,000,000‌

3,905,000‌

Cloverie

PLC

for

Zurich

Insurance

Co.

Ltd.

(3-month

USD

LIBOR

+

4.92%),

5.63%,

06/24/2046

(b)

6,500,000‌

6,467,500‌

Corebridge

Financial,

Inc.

(5-year

Treasury

Constant

Maturity

Rate

+

3.85%),

6.88%,

12/15/2052

(b)

7,921,000‌

7,930,494‌

Equitable

Holdings,

Inc.

,

Series

B

(5-year

Treasury

Constant

Maturity

Rate

+

4.74%),

4.95%,

09/15/2025

(a),(b)

4,373,000‌

4,273,686‌

Liberty

Mutual

Group,

Inc.

(5-year

Treasury

Constant

Maturity

Rate

+

3.32%),

4.13%,

12/15/2051

(b),(d)

12,182,000‌

10,997,322‌

Meiji

Yasuda

Life

Insurance

Co.

(5-year

Swap

rate

+

4.23%),

5.20%,

10/20/2045

(b),(d)

1,210,000‌

1,194,876‌

MetLife,

Inc.

6.40%,

12/15/2066

2,700,000‌

2,764,700‌

9.25%,

04/08/2068

(d)

3,449,000‌

4,042,470‌

MetLife,

Inc.

,

Series

G

(5-year

Treasury

Constant

Maturity

Rate

+

3.58%),

3.85%,

09/15/2025

(a),(b)

12,418,000‌

11,936,225‌

Nippon

Life

Insurance

Co.

(5-year

Treasury

Constant

Maturity

Rate

+

2.65%),

2.75%,

01/21/2051

(b),(d)

6,097,000‌

5,074,810‌

(5-year

Treasury

Constant

Maturity

Rate

+

2.60%),

2.90%,

09/16/2051

(b),(d)

3,509,000‌

2,918,239‌

Prudential

Financial,

Inc.

(5-year

Treasury

Constant

Maturity

Rate

+

3.04%),

3.70%,

10/01/2050

(b)

18,902,000‌

16,522,119‌

(5-year

Treasury

Constant

Maturity

Rate

+

3.16%),

5.13%,

03/01/2052

(b)

5,597,000‌

5,246,313‌

Sumitomo

Life

Insurance

Co.

(5-year

Treasury

Constant

Maturity

Rate

+

2.75%),

3.38%,

04/15/2081

(b),(d)

4,140,000‌

3,582,354‌

Willow

No.

2

Ireland

PLC

for

Zurich

Insurance

Co.

Ltd.

(3-month

USD

LIBOR

+

3.18%),

4.25%,

10/01/2045

(b)

3,000,000‌

2,906,400‌

Zurich

Finance

Ireland

Designated

Activity

Co.

(5-year

Treasury

Constant

Maturity

Rate

+

2.78%),

3.00%,

04/19/2051

(b)

8,000,000‌

6,610,336‌

$

115,292,968‌

Oil

&

Gas

-

1

.74

%

BP

Capital

Markets

PLC

(5-year

Treasury

Constant

Maturity

Rate

+

4.04%),

4.38%,

06/22/2025

(a),(b)

1,780,000‌

1,744,556‌

BONDS

(continued)

Principal

Amount

Value

Oil

&

Gas

(continued)

BP

Capital

Markets

PLC

(continued)

(5-year

Treasury

Constant

Maturity

Rate

+

4.40%),

4.88%,

03/22/2030

(a),(b)

$

3,269,000‌

$

3,118,693‌

(5-year

Treasury

Constant

Maturity

Rate

+

2.15%),

6.45%,

12/01/2033

(a),(b)

9,600,000‌

9,941,654‌

$

14,804,903‌

Pipelines

-

4

.72

%

Enbridge,

Inc.

(5-year

Treasury

Constant

Maturity

Rate

+

4.42%),

7.63%,

01/15/2083

(b)

7,283,000‌

7,474,201‌

(5-year

Treasury

Constant

Maturity

Rate

+

4.43%),

8.50%,

01/15/2084

(b)

600,000‌

651,921‌

Enbridge,

Inc.

,

Series

16-A

(3-month

Term

Secured

Overnight

Financing

Rate

+

4.15%),

6.00%,

01/15/2077

(b)

6,182,000‌

6,042,498‌

Enbridge,

Inc.

,

Series

20-A

(5-year

Treasury

Constant

Maturity

Rate

+

5.31%),

5.75%,

07/15/2080

(b)

2,485,000‌

2,351,799‌

Enterprise

Products

Operating

LLC

,

Series

E

(3-month

Term

Secured

Overnight

Financing

Rate

+

3.29%),

5.25%,

08/16/2077

(b)

4,820,000‌

4,573,727‌

Transcanada

Trust

(6-month

Secured

Overnight

Financing

Rate

+

4.42%),

5.50%,

09/15/2079

(b)

5,233,000‌

4,811,525‌

(5-year

Treasury

Constant

Maturity

Rate

+

3.99%),

5.60%,

03/07/2082

(b)

15,585,000‌

14,227,582‌

$

40,133,253‌

REITs

-

0

.40

%

Scentre

Group

Trust

2

(5-year

Treasury

Constant

Maturity

Rate

+

4.38%),

4.75%,

09/24/2080

(b),(d)

1,410,000‌

1,353,467‌

(5-year

Treasury

Constant

Maturity

Rate

+

4.69%),

5.13%,

09/24/2080

(b),(d)

2,249,000‌

2,078,445‌

$

3,431,912‌

Sovereign

-

0

.08

%

CoBank

ACB

,

Series

J

(5-year

Treasury

Constant

Maturity

Rate

+

3.05%),

4.25%,

01/01/2027

(a),(b)

750,000‌

640,615‌

Telecommunications

-

0

.77

%

Vodafone

Group

PLC

(5-year

Treasury

Constant

Maturity

Rate

+

2.77%),

4.13%,

06/04/2081

(b)

993,000‌

855,295‌

(5-year

Swap

rate

+

4.87%),

7.00%,

04/04/2079

(b)

5,562,000‌

5,737,147‌

$

6,592,442‌

TOTAL

BONDS

a

$

838,793,745‌

INVESTMENT

COMPANIES

-

0

.69

%

Shares

Held

Value

Money

Market

Funds

-

0

.69

%

-

—

Principal

Government

Money

Market

Fund,

Class

R-6

5.22%

(e),(f),(g)

1,066,240‌

$

1,066,240‌

State

Street

Institutional

U.S.

Government

Money

Market

Fund,

Premier

Class

5.26%

(e)

4,820,543‌

4,820,543‌

TOTAL

INVESTMENT

COMPANIES

a

$

5,886,783‌

Total

Investments

$

844,680,528‌

Other

Assets

and

Liabilities

-

0.75%

6,430,066‌

TOTAL

NET

ASSETS

-

100.00%

$

851,110,594‌

19

Schedule

of

Investments

Principal

Spectrum

Preferred

Securities

Active

ETF

March

31,

2024

(unaudited)

See

accompanying

notes.

(a)

Perpetual

security.

Perpetual

securities

pay

an

indefinite

stream

of

interest,

but

they

may

be

called

by

the

issuer

at

an

earlier

date.

Date

shown,

if

any,

reflects

the

next

call

date

or

final

legal

maturity

date.

Rate

shown

is

as

of

period

end.

(b)

Rate

shown

is

as

of

period

end.

The

rate

may

be

a

variable

or

floating

rate

or

a

fixed

rate

which

may

convert

to

a

variable

or

floating

rate

in

the

future.

(c)

Security

or

a

portion

of

the

security

was

on

loan.

At

the

end

of

the

period,

the

value

of

these

securities

totaled

$1,048,149

or

0.12%

of

net

assets.

(d)

Security

exempt

from

registration

under

Rule

144A

of

the

Securities

Act

of

1933.

These

securities

may

be

resold

in

transactions

exempt

from

registration,

normally

to

qualified

institutional

buyers.

At

the

end

of

the

period,

the

value

of

these

securities

totaled

$36,490,388

or

4.29%

of

net

assets.

(e)

1-day

yield

shown

as

of

period

end.

(f)

Affiliated

Security.

Security

is

either

an

affiliate

(and

registered

under

the

Investment

Company

Act

of

1940)

or

an

affiliate

as

defined

by

the

Investment

Company

Act

of

1940

(controls

5.00%

or

more

of

the

outstanding

voting

shares

of

the

security).

Please

see

Affiliated

Securities

sub-schedule

for

transactional

information.

(g)

Security

or

a

portion

of

the

security

was

received

as

collateral

for

securities

lending.

At

the

end

of

the

period,

the

value

of

these

securities

totaled

$1,066,240

or

0.13%

of

net

assets.

Portfolio

Summary

Sector

Percent

Financial

77.04%

Utilities

13.97%

Energy

6.46%

Communications

0.77%

Money

Market

Funds

0.69%

Industrial

0.24%

Government

0.08%

Other

Assets

and

Liabilities

0.75%

TOTAL

NET

ASSETS

100.00%

Affiliated

Securities

June

30,

2023

Value

Purchases

Cost

Sales

Proceeds

March

31,

2024

Value

Principal

Government

Money

Market

Fund,

Class

R-6

5.22%

$

3,970,623‌

$

52,945,988‌

$

55,850,371‌

$

1,066,240‌

$

3,970,623‌

$

52,945,988‌

$

55,850,371‌

$

1,066,240‌

a

a

Income

(a)

Realized

Gain/(Loss)

on

Investments

Realized

Gain

from

Capital

Gain

Distributions

Change

in

Unrealized

Gain/(Loss)

Principal

Government

Money

Market

Fund,

Class

R-6

5.22%

$

—‌

$

—‌

$

—‌

$

—‌

$

—‌

$

—‌

$

—‌

$

—‌

(a)

Amount

excludes

earnings

from

securities

lending

collateral.

20

Schedule

of

Investments

Principal

Spectrum

Tax-Advantaged

Dividend

Active

ETF

March

31,

2024

(unaudited)

See

accompanying

notes.

PREFERRED

STOCKS

-

7

.46

%

Shares

Held

Value

Banks

-

2

.57

%

—

Bank

of

America

Corp.,

Series

NN

4.38%,

11/03/2025

(a)

4,380‌

$

90,359‌

Morgan

Stanley,

Series

I

(3-month

USD

LIBOR

+

3.71%),

6.38%,

10/15/2024

(a)

17,030‌

424,047‌

Morgan

Stanley,

Series

P

6.50%,

10/15/2027

(a)

4,000‌

105,240‌

$

619,646‌

Insurance

-

2

.60

%

Allstate

Corp.,

Series

H

5.10%,

10/15/2024

(a)

11,500‌

258,060‌

MetLife,

Inc.,

Series

F

4.75%,

03/15/2025

(a)

17,250‌

367,425‌

$

625,485‌

Telecommunications

-

2

.29

%

AT&T,

Inc.,

Series

A

5.00%,

12/12/2024

(a)

11,381‌

243,098‌

AT&T,

Inc.,

Series

C

4.75%,

02/18/2025

(a)

15,395‌

309,594‌

$

552,692‌

TOTAL

PREFERRED

STOCKS

a

$

1,797,823‌

BONDS

-

90

.36

%

Principal

Amount

Value

Banks

-

69

.61

%

—

—

Bank

of

America

Corp.

,

Series

DD

(3-month

Term

Secured

Overnight

Financing

Rate

+

4.81%),

6.30%,

03/10/2026

(a),(b)

$

575,000‌

$

575,517‌

Bank

of

Montreal

(5-year

Treasury

Constant

Maturity

Rate

+

2.98%),

4.80%,

08/25/2024

(a),(b)

400,000‌

390,889‌

Bank

of

New

York

Mellon

Corp.

,

Series

G

(5-year

Treasury

Constant

Maturity

Rate

+

4.36%),

4.70%,

09/20/2025

(a),(b)

275,000‌

269,839‌

Bank

of

New

York

Mellon

Corp.

,

Series

H

(5-year

Treasury

Constant

Maturity

Rate

+

3.35%),

3.70%,

03/20/2026

(a),(b)

230,000‌

216,945‌

Bank

of

New

York

Mellon

Corp.

,

Series

I

(5-year

Treasury

Constant

Maturity

Rate

+

2.63%),

3.75%,

12/20/2026

(a),(b)

100,000‌

91,660‌

Bank

of

Nova

Scotia

(5-year

Treasury

Constant

Maturity

Rate

+

4.55%),

4.90%,

06/04/2025

(a),(b)

625,000‌

615,015‌

(5-year

Treasury

Constant

Maturity

Rate

+

4.38%),

8.63%,

10/27/2082

(b)

300,000‌

312,360‌

BNP

Paribas

SA

(5-year

Treasury

Constant

Maturity

Rate

+

4.90%),

7.75%,

08/16/2029

(a),(b),(c),(d)

200,000‌

204,737‌

Citigroup,

Inc.

,

Series

X

(5-year

Treasury

Constant

Maturity

Rate

+

3.42%),

3.88%,

02/18/2026

(a),(b)

1,055,000‌

995,681‌

Citizens

Financial

Group,

Inc.

,

Series

F

(5-year

Treasury

Constant

Maturity

Rate

+

5.31%),

5.65%,

10/06/2025

(a),(b)

575,000‌

561,827‌

Fifth

Third

Bancorp

,

Series

L

(5-year

Treasury

Constant

Maturity

Rate

+

4.22%),

4.50%,

09/30/2025

(a),(b)

548,000‌

527,826‌

BONDS

(continued)

Principal

Amount

Value

Banks

(continued)

Goldman

Sachs

Group,

Inc.

,

Series

U

(5-year

Treasury

Constant

Maturity

Rate

+

2.92%),

3.65%,

08/10/2026

(a),(b)

$

585,000‌

$

534,317‌

HSBC

Holdings

PLC

(5-year

Swap

Rate

+

4.37%),

6.38%,

03/30/2025

(a),(b),(d)

861,000‌

854,905‌

Huntington

Bancshares,

Inc.

,

Series

F

(10-year

Treasury

Constant

Maturity

Rate

+

4.95%),

5.63%,

07/15/2030

(a),(b)

575,000‌

523,007‌

ING

Groep

NV

(5-year

Treasury

Constant

Maturity

Rate

+

4.34%),

5.75%,

11/16/2026

(a),(b),(d)

861,000‌

819,712‌

JPMorgan

Chase

&

Co.

(5-year

Treasury

Constant

Maturity

Rate

+

2.74%),

6.88%,

06/01/2029

(a),(b)

600,000‌

620,863‌

JPMorgan

Chase

&

Co.

,

Series

KK

(5-year

Treasury

Constant

Maturity

Rate

+

2.85%),

3.65%,

06/01/2026

(a),(b)

110,000‌

104,471‌

Lloyds

Banking

Group

PLC

(5-year

Swap

Rate

+

4.50%),

7.50%,

09/27/2025

(a),(b),(d)

861,000‌

857,558‌

M&T

Bank

Corp.

,

Series

F

(3-month

USD

LIBOR

+

3.78%),

5.13%,

11/01/2026

(a),(b)

247,000‌

218,647‌

M&T

Bank

Corp.

,

Series

I

(5-year

Treasury

Constant

Maturity

Rate

+

2.68%),

3.50%,

09/01/2026

(a),(b)

300,000‌

230,103‌

NatWest

Group

PLC

(5-year

Swap

rate

+

5.72%),

8.00%,

08/10/2025

(a),(b),(d)

861,000‌

865,673‌

Nordea

Bank

Abp

(5-year

Treasury

Constant

Maturity

Rate

+

4.11%),

6.63%,

03/26/2026

(a),(b),(c),(d)

861,000‌

852,315‌

PNC

Financial

Services

Group,

Inc.

,

Series

T

(5-year

Treasury

Constant

Maturity

Rate

+

2.60%),

3.40%,

09/15/2026

(a),(b)

400,000‌

349,616‌

PNC

Financial

Services

Group,

Inc.

,

Series

U

(5-year

Treasury

Constant

Maturity

Rate

+

3.00%),

6.00%,

05/15/2027

(a),(b)

600,000‌

586,529‌

PNC

Financial

Services

Group,

Inc.

,

Series

V

(5-year

Treasury

Constant

Maturity

Rate

+

3.24%),

6.20%,

09/15/2027

(a),(b)

100,000‌

99,739‌

State

Street

Corp.

,

Series

I

(5-year

Treasury

Constant

Maturity

Rate

+

2.61%),

6.70%,

03/15/2029

(a),(b)

800,000‌

811,778‌

Toronto-Dominion

Bank

(5-year

Treasury

Constant

Maturity

Rate

+

4.07%),

8.13%,

10/31/2082

(b)

414,000‌

434,225‌

Truist

Financial

Corp.

,

Series

N

(5-year

Treasury

Constant

Maturity

Rate

+

3.00%),

4.80%,

09/01/2024

(a),(b)

400,000‌

387,166‌

Truist

Financial

Corp.

,

Series

P

(5-year

Treasury

Constant

Maturity

Rate

+

4.61%),

4.95%,

09/01/2025

(a),(b)

575,000‌

564,123‌

21

Schedule

of

Investments

Principal

Spectrum

Tax-Advantaged

Dividend

Active

ETF

March

31,

2024

(unaudited)

See

accompanying

notes.

BONDS

(continued)

Principal

Amount

Value

Banks

(continued)

U.S.

Bancorp

,

Series

N

(5-year

Treasury

Constant

Maturity

Rate

+

2.54%),

3.70%,

01/15/2027

(a),(b)

$

809,000‌

$

701,654‌

UBS

Group

AG

(5-year

Treasury

Constant

Maturity

Rate

+

4.75%),

9.25%,

11/13/2028

(a),(b),(c)

800,000‌

866,780‌

Wells

Fargo

&

Co.

(5-year

Treasury

Constant

Maturity

Rate

+

3.61%),

7.63%,

09/15/2028

(a),(b)

400,000‌

427,483‌

Wells

Fargo

&

Co.

,

Series

BB

(5-year

Treasury

Constant

Maturity

Rate

+

3.45%),

3.90%,

03/15/2026

(a),(b)

328,000‌

312,068‌

$

16,785,028‌

Diversified

Financial

Services

-

11

.20

%

American

Express

Co.

,

Series

D

(5-year

Treasury

Constant

Maturity

Rate

+

2.85%),

3.55%,

09/15/2026

(a),(b)

845,000‌

782,138‌

Capital

One

Financial

Corp.

,

Series

M

(5-year

Treasury

Constant

Maturity

Rate

+

3.16%),

3.95%,

09/01/2026

(a),(b)

209,000‌

185,649‌

Charles

Schwab

Corp.

,

Series

G

(5-year

Treasury

Constant

Maturity

Rate

+

4.97%),

5.38%,

06/01/2025

(a),(b)

375,000‌

372,405‌

Charles

Schwab

Corp.

,

Series

I

(5-year

Treasury

Constant

Maturity

Rate

+

3.17%),

4.00%,

06/01/2026

(a),(b)

328,000‌

306,868‌

Discover

Financial

Services

,

Series

D

(5-year

Treasury

Constant

Maturity

Rate

+

5.78%),

6.13%,

06/23/2025

(a),(b)

575,000‌

576,187‌

Voya

Financial,

Inc.

,

Series

A

(5-year

Treasury

Constant

Maturity

Rate

+

3.36%),

7.76%,

09/15/2028

(a),(b)

460,000‌

476,995‌

$

2,700,242‌

Electric

-

6

.95

%

Dominion

Energy,

Inc.

,

Series

B

(5-year

Treasury

Constant

Maturity

Rate

+

2.99%),

4.65%,

12/15/2024

(a),(b)

460,000‌

450,259‌

BONDS

(continued)

Principal

Amount

Value

Electric

(continued)

Dominion

Energy,

Inc.

,

Series

C

(5-year

Treasury

Constant

Maturity

Rate

+

3.20%),

4.35%,

01/15/2027

(a),(b)

$

700,000‌

$

655,316‌

Duke

Energy

Corp.

(5-year

Treasury

Constant

Maturity

Rate

+

3.39%),

4.88%,

09/16/2024

(a),(b)

575,000‌

569,987‌

$

1,675,562‌

Insurance

-

0

.88

%

MetLife,

Inc.

,

Series

G

(5-year

Treasury

Constant

Maturity

Rate

+

3.58%),

3.85%,

09/15/2025

(a),(b)

220,000‌

211,465‌

Oil

&

Gas

-

1

.72

%

BP

Capital

Markets

PLC

(5-year

Treasury

Constant

Maturity

Rate

+

2.15%),

6.45%,

12/01/2033

(a),(b)

400,000‌

414,235‌

TOTAL

BONDS

a

$

21,786,532‌

INVESTMENT

COMPANIES

-

1

.16

%

Shares

Held

Value

Money

Market

Funds

-

1

.16

%

-

—

State

Street

Institutional

U.S.

Government

Money

Market

Fund,

Premier

Class

5.26%

(e)

280,874‌

$

280,874‌

TOTAL

INVESTMENT

COMPANIES

a

$

280,874‌

Total

Investments

$

23,865,229‌

Other

Assets

and

Liabilities

-

1.02%

246,034‌

TOTAL

NET

ASSETS

-

100.00%

$

24,111,263‌

(a)

Perpetual

security.

Perpetual

securities

pay

an

indefinite

stream

of

interest,

but

they

may

be

called

by

the

issuer

at

an

earlier

date.

Date

shown,

if

any,

reflects

the

next

call

date

or

final

legal

maturity

date.

Rate

shown

is

as

of

period

end.

(b)

Rate

shown

is

as

of

period

end.

The

rate

may

be

a

variable

or

floating

rate

or

a

fixed

rate

which

may

convert

to

a

variable

or

floating

rate

in

the

future.

(c)

Security

exempt

from

registration

under

Rule

144A

of

the

Securities

Act

of

1933.

These

securities

may

be

resold

in

transactions

exempt

from

registration,

normally

to

qualified

institutional

buyers.

At

the

end

of

the

period,

the

value

of

these

securities

totaled

$1,923,832

or

7.98%

of

net

assets.

(d)

Security

is

a

contingent

convertible

security,

("CoCo").

CoCo's

are

hybrid

debt

securities

that

may

convert

to

equity

or

have

their

principal

written

down

upon

occurrence

of

certain

"triggers".

At

the

end

of

the

period,

the

value

of

these

securities

totaled

$4,454,900

or

18.48%

of

net

assets.

(e)

1-day

yield

shown

as

of

period

end.

Portfolio

Summary

Sector

Percent

Financial

86.86%

Utilities

6.95%

Communications

2.29%

Energy

1.72%

Money

Market

Funds

1.16%

Other

Assets

and

Liabilities

1.02%

TOTAL

NET

ASSETS

100.00%

22

Schedule

of

Investments

Principal

U.S.

Mega-Cap

ETF

March

31,

2024

(unaudited)

See

accompanying

notes.

COMMON

STOCKS

-

99

.69

%

Shares

Held

Value

Auto

Manufacturers

-

1

.85

%

-

—

Tesla,

Inc.

(a)

238,957‌

$

42,006,251‌

Banks

-

6

.02

%

Bank

of

America

Corp.

1,319,052‌

50,018,452‌

JPMorgan

Chase

&

Co.

281,723‌

56,429,117‌

Wells

Fargo

&

Co.

524,961‌

30,426,739‌

$

136,874,308‌

Beverages

-

2

.55

%

Coca-Cola

Co.

615,176‌

37,636,468‌

PepsiCo,

Inc.

116,828‌

20,446,068‌

$

58,082,536‌

Chemicals

-

1

.21

%

Linde

PLC

59,205‌

27,490,066‌

Computers

-

8

.93

%

Accenture

PLC,

Class

A

207,322‌

71,859,878‌

Apple,

Inc.

765,743‌

131,309,610‌

$

203,169,488‌

Cosmetics

&

Personal

Care

-

1

.80

%

Procter

&

Gamble

Co.

252,428‌

40,956,443‌

Diversified

Financial

Services

-

6

.23

%

Mastercard,

Inc.,

Class

A

152,587‌

73,481,321‌

Visa,

Inc.,

Class

A

244,736‌

68,300,923‌

$

141,782,244‌

Electric

-

0

.77

%

NextEra

Energy,

Inc.

274,183‌

17,523,036‌

Environmental

Control

-

0

.30

%

Veralto

Corp.

75,553‌

6,698,529‌

Healthcare

-

Products

-

6

.01

%

Abbott

Laboratories

352,851‌

40,105,045‌

Danaher

Corp.

226,521‌

56,566,824‌

Thermo

Fisher

Scientific,

Inc.

68,911‌

40,051,762‌

$

136,723,631‌

Healthcare

-

Services

-

2

.58

%

UnitedHealth

Group,

Inc.

118,631‌

58,686,756‌

Insurance

-

1

.23

%

Berkshire

Hathaway,

Inc.,

Class

B

(a)

66,668‌

28,035,227‌

Internet

-

10

.51

%

Alphabet,

Inc.,

Class

A

(a)

544,511‌

82,183,045‌

Amazon.com,

Inc.

(a)

370,170‌

66,771,265‌

Meta

Platforms,

Inc.,

Class

A

185,815‌

90,228,048‌

$

239,182,358‌

Media

-

2

.26

%

Comcast

Corp.,

Class

A

573,650‌

24,867,728‌

Walt

Disney

Co.

217,462‌

26,608,650‌

$

51,476,378‌

Oil

&

Gas

-

4

.14

%

Chevron

Corp.

232,882‌

36,734,807‌

Exxon

Mobil

Corp.

493,776‌

57,396,522‌

$

94,131,329‌

COMMON

STOCKS

(continued)

Shares

Held

Value

Pharmaceuticals

-

9

.28

%

AbbVie,

Inc.

242,601‌

$

44,177,642‌

Eli

Lilly

&

Co.

56,559‌

44,000,640‌

Johnson

&

Johnson

242,862‌

38,418,340‌

Merck

&

Co.,

Inc.

341,515‌

45,062,904‌

Pfizer,

Inc.

1,424,562‌

39,531,595‌

$

211,191,121‌

Retail

-

7

.94

%

Costco

Wholesale

Corp.

113,355‌

83,047,274‌

Home

Depot,

Inc.

131,958‌

50,619,089‌

McDonald's

Corp.

74,259‌

20,937,325‌

Walmart,

Inc.

430,815‌

25,922,138‌

$

180,525,826‌

Semiconductors

-

11

.14

%

Broadcom,

Inc.

62,558‌

82,914,999‌

NVIDIA

Corp.

145,876‌

131,807,718‌

Texas

Instruments,

Inc.

222,600‌

38,779,146‌

$

253,501,863‌

Software

-

13

.10

%

Adobe,

Inc.

(a)

151,975‌

76,686,585‌

Microsoft

Corp.

383,836‌

161,487,482‌

Salesforce,

Inc.

198,929‌

59,913,436‌

$

298,087,503‌

Telecommunications

-

1

.84

%

Cisco

Systems,

Inc.

840,217‌

41,935,230‌

TOTAL

COMMON

STOCKS

a

$

2,268,060,123‌

INVESTMENT

COMPANIES

-

0

.25

%

Shares

Held

Value

Money

Market

Funds

-

0

.25

%

-

—

State

Street

Institutional

U.S.

Government

Money

Market

Fund,

Premier

Class

5.26%

(b)

5,662,432‌

$

5,662,432‌

TOTAL

INVESTMENT

COMPANIES

a

$

5,662,432‌

Total

Investments

$

2,273,722,555‌

Other

Assets

and

Liabilities

-

0.06%

1,396,913‌

TOTAL

NET

ASSETS

-

100.00%

$

2,275,119,468‌

(a)

Non-income

producing

security.

(b)

1-day

yield

shown

as

of

period

end.

Portfolio

Summary

Sector

Percent

Technology

33.17%

Consumer,

Non-cyclical

22.22%

Communications

14.61%

Financial

13.48%

Consumer,

Cyclical

9.79%

Energy

4.14%

Basic

Materials

1.21%

Utilities

0.77%

Industrial

0.30%

Money

Market

Funds

0.25%

Other

Assets

and

Liabilities

0.06%

TOTAL

NET

ASSETS

100.00%

23

Schedule

of

Investments

Principal

U.S.

Small-Cap

ETF

March

31,

2024

(unaudited)

See

accompanying

notes.

COMMON

STOCKS

-

99

.54

%

Shares

Held

Value

Advertising

-

0

.03

%

-

—

Advantage

Solutions,

Inc.

(a)

32,826‌

$

142,137‌

Aerospace

&

Defense

-

0

.46

%

Leonardo

DRS,

Inc.

(a)

48,609‌

1,073,773‌

Moog,

Inc.,

Class

A

8,330‌

1,329,884‌

$

2,403,657‌

Agriculture

-

0

.29

%

Andersons,

Inc.

6,509‌

373,421‌

Dole

PLC

20,208‌

241,082‌

Fresh

Del

Monte

Produce,

Inc.

8,917‌

231,040‌

Turning

Point

Brands,

Inc.

5,460‌

159,978‌

Universal

Corp.

5,249‌

271,478‌

Vital

Farms,

Inc.

(a)

10,944‌

254,448‌

$

1,531,447‌

Apparel

-

0

.50

%

Kontoor

Brands,

Inc.

17,216‌

1,037,264‌

Oxford

Industries,

Inc.

6,287‌

706,659‌

Steven

Madden

Ltd.

21,189‌

895,871‌

$

2,639,794‌

Auto

Manufacturers

-

0

.36

%

Blue

Bird

Corp.

(a)

20,307‌

778,570‌

REV

Group,

Inc.

11,775‌

260,110‌

Wabash

National

Corp.

27,857‌

834,039‌

$

1,872,719‌

Auto

Parts

&

Equipment

-

0

.45

%

Fox

Factory

Holding

Corp.

(a)

13,852‌

721,273‌

Standard

Motor

Products,

Inc.

4,575‌

153,491‌

Visteon

Corp.

(a)

9,847‌

1,158,106‌

XPEL,

Inc.

(a)

5,637‌

304,511‌

$

2,337,381‌

Banks

-

7

.33

%

Amalgamated

Financial

Corp.

13,881‌

333,144‌

Ameris

Bancorp

34,922‌

1,689,526‌

Bancorp,

Inc.

(a)

35,344‌

1,182,610‌

Bank

of

NT

Butterfield

&

Son

Ltd.

19,777‌

632,666‌

Byline

Bancorp,

Inc.

11,867‌

257,751‌

Cadence

Bank

133,128‌

3,860,712‌

Central

Pacific

Financial

Corp.

16,192‌

319,792‌

City

Holding

Co.

6,702‌

698,482‌

ConnectOne

Bancorp,

Inc.

15,344‌

299,208‌

Customers

Bancorp,

Inc.

(a)

30,446‌

1,615,465‌

CVB

Financial

Corp.

85,645‌

1,527,907‌

Eagle

Bancorp,

Inc.

22,794‌

535,431‌

Enterprise

Financial

Services

Corp.

13,761‌

558,146‌

FB

Financial

Corp.

14,025‌

528,181‌

First

BanCorp

107,996‌

1,894,250‌

First

Merchants

Corp.

21,282‌

742,742‌

Fulton

Financial

Corp.

98,288‌

1,561,796‌

Heartland

Financial

USA,

Inc.

18,426‌

647,674‌

Heritage

Financial

Corp.

19,120‌

370,737‌

Independent

Bank

Corp.

23,039‌

1,198,489‌

Independent

Bank

Corp.

9,402‌

238,341‌

International

Bancshares

Corp.

20,023‌

1,124,091‌

Live

Oak

Bancshares,

Inc.

18,783‌

779,682‌

Mercantile

Bank

Corp.

5,914‌

227,630‌

Merchants

Bancorp

11,735‌

506,717‌

Metropolitan

Bank

Holding

Corp.

(a)

10,938‌

421,113‌

Nicolet

Bankshares,

Inc.

4,133‌

355,397‌

OFG

Bancorp

20,052‌

738,114‌

Old

National

Bancorp

183,355‌

3,192,211‌

Old

Second

Bancorp,

Inc.

21,502‌

297,588‌

Peoples

Bancorp,

Inc.

12,874‌

381,199‌

Preferred

Bank

8,254‌

633,660‌

Premier

Financial

Corp.

14,487‌

294,086‌

QCR

Holdings,

Inc.

5,097‌

309,592‌

S&T

Bancorp,

Inc.

15,539‌

498,491‌

SouthState

Corp.

36,893‌

3,137,012‌

TriCo

Bancshares

9,456‌

347,792‌

Triumph

Financial,

Inc.

(a)

13,946‌

1,106,197‌

UMB

Financial

Corp.

21,719‌

1,889,336‌

Veritex

Holdings,

Inc.

34,170‌

700,143‌

COMMON

STOCKS

(continued)

Shares

Held

Value

Banks

(continued)

Westamerica

BanCorp

14,772‌

$

722,055‌

$

38,355,156‌

Beverages

-

0

.34

%

Coca-Cola

Consolidated,

Inc.

1,378‌

1,166,353‌

Vita

Coco

Co.,

Inc.

(a)

25,935‌

633,592‌

$

1,799,945‌

Biotechnology

-

3

.83

%

ACADIA

Pharmaceuticals,

Inc.

(a)

49,771‌

920,266‌

ADMA

Biologics,

Inc.

(a)

78,396‌

517,414‌

Amicus

Therapeutics,

Inc.

(a)

166,607‌

1,962,631‌

ANI

Pharmaceuticals,

Inc.

(a)

6,702‌

463,309‌

Arcellx,

Inc.

(a)

25,933‌

1,803,640‌

Arcturus

Therapeutics

Holdings,

Inc.

(a)

11,040‌

372,821‌

Ardelyx,

Inc.

(a)

93,354‌

681,484‌

Bridgebio

Pharma,

Inc.

(a)

90,495‌

2,798,105‌

Chinook

Therapeutics,

Inc.

(a),(b)

9,658‌

3,863‌

Dynavax

Technologies

Corp.

(a)

94,662‌

1,174,755‌

Evolus,

Inc.

(a)

20,372‌

285,208‌

EyePoint

Pharmaceuticals,

Inc.

(a)

1,023‌

21,145‌

Halozyme

Therapeutics,

Inc.

(a)

66,952‌

2,723,607‌

Innoviva,

Inc.

(a)

30,905‌

470,992‌

Intra-Cellular

Therapies,

Inc.

(a)

40,043‌

2,770,976‌

Kiniksa

Pharmaceuticals

Ltd.,

Class

A

(a)

18,597‌

366,919‌

Ligand

Pharmaceuticals,

Inc.

(a)

4,767‌

348,468‌

Liquidia

Corp.

(a)

19,390‌

286,003‌

MacroGenics,

Inc.

(a)

19,505‌

287,114‌

Organogenesis

Holdings,

Inc.

(a)

26,937‌

76,501‌

Veracyte,

Inc.

(a)

30,543‌

676,833‌

Vericel

Corp.

(a)

16,263‌

846,001‌

Zymeworks,

Inc.

(a)

19,589‌

206,076‌

$

20,064,131‌

Building

Materials

-

3

.79

%

AAON,

Inc.

22,661‌

1,996,434‌

American

Woodmark

Corp.

(a)

6,427‌

653,369‌

Apogee

Enterprises,

Inc.

8,036‌

475,731‌

Boise

Cascade

Co.

14,111‌

2,164,204‌

Gibraltar

Industries,

Inc.

(a)

10,210‌

822,211‌

Griffon

Corp.

26,509‌

1,944,170‌

JELD-WEN

Holding,

Inc.

(a)

25,976‌

551,471‌

LSI

Industries,

Inc.

9,862‌

149,113‌

Masonite

International

Corp.

(a)

15,781‌

2,074,412‌

Masterbrand,

Inc.

(a)

44,511‌

834,136‌

Modine

Manufacturing

Co.

(a)

20,720‌

1,972,337‌

Simpson

Manufacturing

Co.,

Inc.

12,939‌

2,654,824‌

Summit

Materials,

Inc.,

Class

A

(a)

32,108‌

1,431,054‌

UFP

Industries,

Inc.

16,981‌

2,088,833‌

$

19,812,299‌

Chemicals

-

1

.32

%

AdvanSix,

Inc.

7,250‌

207,350‌

Balchem

Corp.

4,547‌

704,557‌

Cabot

Corp.

13,492‌

1,243,962‌

Hawkins,

Inc.

4,591‌

352,589‌

HB

Fuller

Co.

14,027‌

1,118,513‌

Ingevity

Corp.

(a)

10,017‌

477,811‌

Innospec,

Inc.

3,555‌

458,382‌

Koppers

Holdings,

Inc.

6,313‌

348,288‌

Orion

SA

16,742‌

393,772‌

Quaker

Chemical

Corp.

3,937‌

808,069‌

Rogers

Corp.

(a)

6,588‌

781,930‌

$

6,895,223‌

Coal

-

2

.00

%

Alpha

Metallurgical

Resources,

Inc.

7,862‌

2,603,659‌

Arch

Resources,

Inc.

13,612‌

2,188,674‌

CONSOL

Energy,

Inc.

13,316‌

1,115,348‌

Hallador

Energy

Co.

(a)

10,704‌

57,052‌

Peabody

Energy

Corp.

74,618‌

1,810,233‌

Ramaco

Resources,

Inc.,

Class

A

52,111‌

877,549‌

SunCoke

Energy,

Inc.

23,130‌

260,675‌

Warrior

Met

Coal,

Inc.

25,802‌

1,566,181‌

$

10,479,371‌

24

Schedule

of

Investments

Principal

U.S.

Small-Cap

ETF

March

31,

2024

(unaudited)

See

accompanying

notes.

COMMON

STOCKS

(continued)

Shares

Held

Value

Commercial

Services

-

5

.41

%

Adtalem

Global

Education,

Inc.

(a)

18,703‌

$

961,334‌

Alarm.com

Holdings,

Inc.

(a)

12,716‌

921,529‌

AMN

Healthcare

Services,

Inc.

(a)

26,080‌

1,630,261‌

API

Group

Corp.

(a)

72,675‌

2,853,947‌

Barrett

Business

Services,

Inc.

2,188‌

277,263‌

Brink's

Co.

15,005‌

1,386,162‌

CBIZ,

Inc.

(a)

13,011‌

1,021,364‌

CorVel

Corp.

(a)

1,685‌

443,088‌

CRA

International,

Inc.

1,959‌

293,027‌

Cross

Country

Healthcare,

Inc.

(a)

17,785‌

332,935‌

EVERTEC,

Inc.

25,482‌

1,016,732‌

First

Advantage

Corp.

18,104‌

293,647‌

Huron

Consulting

Group,

Inc.

(a)

6,370‌

615,469‌

ICF

International,

Inc.

6,436‌

969,455‌

Insperity,

Inc.

14,433‌

1,582,001‌

Kforce,

Inc.

7,253‌

511,482‌

LiveRamp

Holdings,

Inc.

(a)

24,569‌

847,631‌

Medifast,

Inc.

8,020‌

307,326‌

National

Research

Corp.

3,643‌

144,299‌

Payoneer

Global,

Inc.

(a)

221,716‌

1,077,540‌

Perdoceo

Education

Corp.

15,833‌

278,027‌

PROG

Holdings,

Inc.

33,235‌

1,144,613‌

Progyny,

Inc.

(a)

35,206‌

1,343,109‌

StoneCo

Ltd.,

Class

A

(a)

189,743‌

3,151,631‌

Stride,

Inc.

(a)

23,504‌

1,481,927‌

Target

Hospitality

Corp.

(a)

22,460‌

244,140‌

Transcat,

Inc.

(a)

2,687‌

299,412‌

TriNet

Group,

Inc.

15,232‌

2,018,088‌

Upbound

Group,

Inc.

14,451‌

508,820‌

ZipRecruiter,

Inc.,

Class

A

(a)

32,589‌

374,448‌

$

28,330,707‌

Computers

-

4

.32

%

ASGN,

Inc.

(a)

17,803‌

1,865,042‌

Corsair

Gaming,

Inc.

(a)

36,388‌

449,028‌

Cricut,

Inc.,

Class

A

24,432‌

116,296‌

ExlService

Holdings,

Inc.

(a)

51,666‌

1,642,979‌

Grid

Dynamics

Holdings,

Inc.

(a)

29,558‌

363,268‌

Insight

Enterprises,

Inc.

(a)

9,090‌

1,686,377‌

Integral

Ad

Science

Holding

Corp.

(a)

46,855‌

467,144‌

Mitek

Systems,

Inc.

(a)

33,664‌

474,663‌

Parsons

Corp.

(a)

35,016‌

2,904,577‌

Qualys,

Inc.

(a)

15,098‌

2,519,403‌

Rapid7,

Inc.

(a)

30,619‌

1,501,556‌

Super

Micro

Computer,

Inc.

(a)

6,005‌

6,065,230‌

Varonis

Systems,

Inc.

(a)

54,247‌

2,558,831‌

$

22,614,394‌

Cosmetics

&

Personal

Care

-

0

.88

%

elf

Beauty,

Inc.

(a)

20,615‌

4,041,159‌

Inter

Parfums,

Inc.

3,912‌

549,675‌

$

4,590,834‌

Distribution

&

Wholesale

-

0

.52

%

G-III

Apparel

Group

Ltd.

(a)

23,433‌

679,792‌

Hudson

Technologies,

Inc.

(a)

20,925‌

230,384‌

Rush

Enterprises,

Inc.,

Class

A

22,414‌

1,199,597‌

ScanSource,

Inc.

(a)

13,549‌

596,698‌

$

2,706,471‌

Diversified

Financial

Services

-

3

.19

%

AssetMark

Financial

Holdings,

Inc.

(a)

9,690‌

343,123‌

Enact

Holdings,

Inc.

24,647‌

768,493‌

Enova

International,

Inc.

(a)

22,136‌

1,390,805‌

Federal

Agricultural

Mortgage

Corp.,

Class

C

4,420‌

870,210‌

Hamilton

Lane,

Inc.,

Class

A

14,812‌

1,670,201‌

Mr.

Cooper

Group,

Inc.

(a)

37,984‌

2,960,853‌

Pagseguro

Digital

Ltd.,

Class

A

(a)

259,774‌

3,709,573‌

PJT

Partners,

Inc.,

Class

A

20,596‌

1,941,379‌

Victory

Capital

Holdings,

Inc.,

Class

A

36,112‌

1,532,232‌

Virtus

Investment

Partners,

Inc.

3,772‌

935,380‌

World

Acceptance

Corp.

(a)

4,084‌

592,098‌

$

16,714,347‌

COMMON

STOCKS

(continued)

Shares

Held

Value

Electric

-

1

.45

%

ALLETE,

Inc.

31,467‌

$

1,876,692‌

Black

Hills

Corp.

45,306‌

2,473,708‌

Genie

Energy

Ltd.,

Class

B

26,948‌

406,376‌

MGE

Energy,

Inc.

15,916‌

1,252,907‌

Otter

Tail

Corp.

18,163‌

1,569,283‌

$

7,578,966‌

Electrical

Components

&

Equipment

-

1

.45

%

Belden,

Inc.

12,741‌

1,179,944‌

Encore

Wire

Corp.

9,881‌

2,596,529‌

Energizer

Holdings,

Inc.

15,350‌

451,904‌

EnerSys

15,495‌

1,463,658‌

Insteel

Industries,

Inc.

7,315‌

279,579‌

Novanta,

Inc.

(a)

7,192‌

1,256,946‌

Powell

Industries,

Inc.

2,438‌

346,927‌

$

7,575,487‌

Electronics

-

2

.47

%

Atkore,

Inc.

23,539‌

4,480,884‌

Badger

Meter,

Inc.

7,399‌

1,197,232‌

Bel

Fuse,

Inc.,

Class

B

6,616‌

399,011‌

CTS

Corp.

12,746‌

596,385‌

ESCO

Technologies,

Inc.

5,904‌

632,023‌

Kimball

Electronics,

Inc.

(a)

14,050‌

304,183‌

Mesa

Laboratories,

Inc.

3,008‌

330,068‌

Napco

Security

Technologies,

Inc.

16,806‌

674,929‌

NVE

Corp.

4,258‌

383,986‌

OSI

Systems,

Inc.

(a)

5,334‌

761,802‌

Plexus

Corp.

(a)

7,373‌

699,108‌

Sanmina

Corp.

(a)

17,742‌

1,103,198‌

Vishay

Intertechnology,

Inc.

60,165‌

1,364,542‌

$

12,927,351‌

Energy

-

Alternate

Sources

-

0

.04

%

Montauk

Renewables,

Inc.

(a)

14,829‌

61,689‌

REX

American

Resources

Corp.

(a)

2,554‌

149,945‌

$

211,634‌

Engineering

&

Construction

-

2

.53

%

Arcosa,

Inc.

15,562‌

1,336,153‌

Comfort

Systems

USA,

Inc.

15,067‌

4,786,937‌

Construction

Partners,

Inc.,

Class

A

(a)

16,014‌

899,186‌

Frontdoor,

Inc.

(a)

26,551‌

865,032‌

IES

Holdings,

Inc.

(a)

3,046‌

370,515‌

Limbach

Holdings,

Inc.

(a)

9,178‌

380,153‌

MYR

Group,

Inc.

(a)

6,529‌

1,154,001‌

Primoris

Services

Corp.

23,197‌

987,496‌

Sterling

Infrastructure,

Inc.

(a)

22,072‌

2,434,762‌

$

13,214,235‌

Entertainment

-

0

.31

%

Accel

Entertainment,

Inc.

(a)

11,246‌

132,590‌

IMAX

Corp.

(a)

47,801‌

772,942‌

Lions

Gate

Entertainment

Corp.,

Class

B

(a)

54,195‌

504,555‌

Monarch

Casino

&

Resort,

Inc.

2,949‌

221,146‌

$

1,631,233‌

Environmental

Control

-

0

.06

%

CECO

Environmental

Corp.

(a)

13,040‌

300,181‌

Food

-

0

.97

%

Cal-Maine

Foods,

Inc.

19,639‌

1,155,755‌

John

B

Sanfilippo

&

Son,

Inc.

1,991‌

210,887‌

Lancaster

Colony

Corp.

3,254‌

675,628‌

Simply

Good

Foods

Co.

(a)

20,162‌

686,113‌

Sprouts

Farmers

Market,

Inc.

(a)

35,998‌

2,321,151‌

$

5,049,534‌

Forest

Products

&

Paper

-

0

.14

%

Sylvamo

Corp.

11,701‌

722,420‌

Gas

-

0

.87

%

Chesapeake

Utilities

Corp.

16,511‌

1,771,630‌

ONE

Gas,

Inc.

43,209‌

2,788,277‌

$

4,559,907‌

Hand

&

Machine

Tools

-

0

.26

%

Cadre

Holdings,

Inc.

10,478‌

379,304‌

Franklin

Electric

Co.,

Inc.

9,051‌

966,737‌

$

1,346,041‌

25

Schedule

of

Investments

Principal

U.S.

Small-Cap

ETF

March

31,

2024

(unaudited)

See

accompanying

notes.

COMMON

STOCKS

(continued)

Shares

Held

Value

Healthcare

-

Products

-

5

.28

%

Artivion,

Inc.

(a)

11,756‌

$

248,757‌

Atrion

Corp.

419‌

194,227‌

Avanos

Medical,

Inc.

(a)

15,819‌

314,956‌

Axonics,

Inc.

(a)

27,017‌

1,863,362‌

CONMED

Corp.

25,183‌

2,016,655‌

Haemonetics

Corp.

(a)

17,954‌

1,532,374‌

Inari

Medical,

Inc.

(a)

35,822‌

1,718,740‌

Inmode

Ltd.

(a)

75,351‌

1,628,335‌

Integer

Holdings

Corp.

(a)

10,527‌

1,228,290‌

Lantheus

Holdings,

Inc.

(a)

50,012‌

3,112,747‌

LeMaitre

Vascular,

Inc.

4,577‌

303,730‌

LivaNova

PLC

(a)

27,040‌

1,512,618‌

Merit

Medical

Systems,

Inc.

(a)

25,286‌

1,915,415‌

MiMedx

Group,

Inc.

(a)

33,572‌

258,504‌

Neogen

Corp.

(a)

109,691‌

1,730,924‌

OmniAb,

Inc.,

Earnout

Shares

(a)

1,130‌

—‌

OmniAb,

Inc.,

Earnout

Shares

(a)

1,130‌

—‌

Omnicell,

Inc.

(a)

27,657‌

808,414‌

OraSure

Technologies,

Inc.

(a)

38,638‌

237,624‌

Patterson

Cos.,

Inc.

49,477‌

1,368,039‌

Quanterix

Corp.

(a)

16,795‌

395,690‌

RxSight,

Inc.

(a)

19,256‌

993,224‌

Semler

Scientific,

Inc.

(a)

2,713‌

79,247‌

STAAR

Surgical

Co.

(a)

48,270‌

1,847,776‌

Tactile

Systems

Technology,

Inc.

(a)

14,744‌

239,590‌

Twist

Bioscience

Corp.

(a)

25,096‌

861,044‌

UFP

Technologies,

Inc.

(a)

2,955‌

745,251‌

Varex

Imaging

Corp.

(a)

15,830‌

286,523‌

Zynex,

Inc.

(a),(c)

15,228‌

188,370‌

$

27,630,426‌

Healthcare

-

Services

-

1

.71

%

Accolade,

Inc.

(a)

15,547‌

162,933‌

Addus

HomeCare

Corp.

(a)

3,993‌

412,637‌

Astrana

Health,

Inc.

(a)

8,815‌

370,142‌

Ensign

Group,

Inc.

12,453‌

1,549,402‌

HealthEquity,

Inc.

(a)

36,717‌

2,997,209‌

LifeStance

Health

Group,

Inc.

(a),(c)

53,086‌

327,541‌

National

HealthCare

Corp.

5,255‌

496,650‌

Pediatrix

Medical

Group,

Inc.

(a)

36,184‌

362,925‌

Pennant

Group,

Inc.

(a)

6,203‌

121,765‌

RadNet,

Inc.

(a)

19,046‌

926,778‌

Select

Medical

Holdings

Corp.

26,316‌

793,427‌

U.S.

Physical

Therapy,

Inc.

3,641‌

410,960‌

$

8,932,369‌

Home

Builders

-

3

.84

%

Beazer

Homes

USA,

Inc.

(a)

15,367‌

504,038‌

Cavco

Industries,

Inc.

(a)

2,551‌

1,018,002‌

Century

Communities,

Inc.

6,840‌

660,060‌

Dream

Finders

Homes,

Inc.,

Class

A

(a)

13,115‌

573,519‌

Forestar

Group,

Inc.

(a)

10,558‌

424,326‌

Green

Brick

Partners,

Inc.

(a)

11,079‌

667,288‌

Hovnanian

Enterprises,

Inc.,

Class

A

(a)

2,415‌

379,010‌

Installed

Building

Products,

Inc.

7,576‌

1,960,139‌

KB

Home

41,663‌

2,953,073‌

Landsea

Homes

Corp.

(a)

6,919‌

100,533‌

LCI

Industries

8,155‌

1,003,554‌

M/I

Homes,

Inc.

(a)

11,661‌

1,589,278‌

MDC

Holdings,

Inc.

13,566‌

853,437‌

Meritage

Homes

Corp.

11,914‌

2,090,430‌

Skyline

Champion

Corp.

(a)

10,528‌

894,985‌

Taylor

Morrison

Home

Corp.

(a)

31,280‌

1,944,678‌

Tri

Pointe

Homes,

Inc.

(a)

26,285‌

1,016,178‌

Winnebago

Industries,

Inc.

19,417‌

1,436,858‌

$

20,069,386‌

Home

Furnishings

-

0

.17

%

Daktronics,

Inc.

(a)

64,556‌

642,978‌

Ethan

Allen

Interiors,

Inc.

7,437‌

257,097‌

$

900,075‌

Household

Products

&

Wares

-

0

.53

%

Central

Garden

&

Pet

Co.

(a)

3,580‌

153,332‌

COMMON

STOCKS

(continued)

Shares

Held

Value

Household

Products

&

Wares

(continued)

Central

Garden

&

Pet

Co.,

Class

A

(a)

8,596‌

$

317,364‌

Helen

of

Troy

Ltd.

(a)

8,800‌

1,014,112‌

Quanex

Building

Products

Corp.

8,252‌

317,124‌

WD-40

Co.

3,787‌

959,285‌

$

2,761,217‌

Insurance

-

3

.60

%

American

Equity

Investment

Life

Holding

Co.

(a)

46,181‌

2,596,296‌

Essent

Group

Ltd.

37,879‌

2,254,179‌

Goosehead

Insurance,

Inc.,

Class

A

(a)

17,890‌

1,191,832‌

HCI

Group,

Inc.

9,800‌

1,137,584‌

Jackson

Financial,

Inc.,

Class

A

59,503‌

3,935,528‌

NMI

Holdings,

Inc.,

Class

A

(a)

39,249‌

1,269,313‌

Palomar

Holdings,

Inc.

(a)

13,037‌

1,092,892‌

Selective

Insurance

Group,

Inc.

25,974‌

2,835,581‌

SiriusPoint

Ltd.

(a)

47,019‌

597,611‌

Skyward

Specialty

Insurance

Group,

Inc.

(a)

41,121‌

1,538,337‌

Universal

Insurance

Holdings,

Inc.

19,602‌

398,313‌

$

18,847,466‌

Internet

-

2

.05

%

Cargurus,

Inc.

(a)

43,544‌

1,004,996‌

ePlus,

Inc.

(a)

8,454‌

663,977‌

HealthStream,

Inc.

4,267‌

113,758‌

Opendoor

Technologies,

Inc.

(a)

549,164‌

1,663,967‌

Perficient,

Inc.

(a)

9,911‌

557,890‌

Q2

Holdings,

Inc.

(a)

29,933‌

1,573,279‌

Shutterstock,

Inc.

25,673‌

1,176,080‌

Solo

Brands,

Inc.,

Class

A

(a)

17,265‌

37,465‌

Sprinklr,

Inc.,

Class

A

(a)

75,454‌

925,821‌

Squarespace,

Inc.,

Class

A

(a)

32,526‌

1,185,247‌

TechTarget,

Inc.

(a)

8,684‌

287,267‌

Yelp,

Inc.

(a)

39,483‌

1,555,630‌

$

10,745,377‌

Iron

&

Steel

-

0

.85

%

Carpenter

Technology

Corp.

25,386‌

1,813,068‌

Commercial

Metals

Co.

45,009‌

2,645,179‌

$

4,458,247‌

Leisure

Time

-

0

.25

%

Acushnet

Holdings

Corp.

10,533‌

694,651‌

Malibu

Boats,

Inc.,

Class

A

(a)

6,741‌

291,751‌

MasterCraft

Boat

Holdings,

Inc.

(a)

4,306‌

102,138‌

Xponential

Fitness,

Inc.,

Class

A

(a)

13,784‌

227,988‌

$

1,316,528‌

Machinery

-

Construction

&

Mining

-

0

.50

%

Terex

Corp.

40,955‌

2,637,502‌

Machinery

-

Diversified

-

1

.55

%

Alamo

Group,

Inc.

3,203‌

731,341‌

Applied

Industrial

Technologies,

Inc.

11,964‌

2,363,488‌

CSW

Industrials,

Inc.

4,435‌

1,040,451‌

DXP

Enterprises,

Inc.

(a)

3,869‌

207,881‌

Kadant,

Inc.

4,396‌

1,442,328‌

Tennant

Co.

6,824‌

829,867‌

Watts

Water

Technologies,

Inc.,

Class

A

6,946‌

1,476,372‌

$

8,091,728‌

Media

-

0

.57

%

AMC

Networks,

Inc.,

Class

A

(a)

21,168‌

256,768‌

Gray

Television,

Inc.

46,598‌

294,499‌

Liberty

Latin

America

Ltd.,

Class

A

(a)

16,541‌

115,291‌

Liberty

Latin

America

Ltd.,

Class

C

(a)

46,293‌

323,588‌

Sinclair,

Inc.

16,537‌

222,753‌

TEGNA,

Inc.

119,708‌

1,788,438‌

$

3,001,337‌

Metal

Fabrication

&

Hardware

-

0

.74

%

Mueller

Industries,

Inc.

36,760‌

1,982,467‌

Olympic

Steel,

Inc.

3,082‌

218,452‌

Ryerson

Holding

Corp.

9,388‌

314,498‌

Standex

International

Corp.

3,496‌

637,041‌

Worthington

Enterprises,

Inc.

11,857‌

737,861‌

$

3,890,319‌

Mining

-

0

.14

%

Constellium

SE

(a)

24,507‌

541,850‌

26

Schedule

of

Investments

Principal

U.S.

Small-Cap

ETF

March

31,

2024

(unaudited)

See

accompanying

notes.

COMMON

STOCKS

(continued)

Shares

Held

Value

Mining

(continued)

U.S.

Lime

&

Minerals,

Inc.

556‌

$

165,766‌

$

707,616‌

Miscellaneous

Manufacturers

-

0

.72

%

Fabrinet

(a)

10,292‌

1,945,394‌

Federal

Signal

Corp.

16,135‌

1,369,377‌

Materion

Corp.

3,624‌

477,462‌

$

3,792,233‌

Multi-National

-

0

.07

%

Banco

Latinoamericano

de

Comercio

Exterior

SA

12,510‌

370,546‌

Oil

&

Gas

-

4

.43

%

California

Resources

Corp.

15,723‌

866,337‌

Chord

Energy

Corp.

14,019‌

2,498,747‌

CNX

Resources

Corp.

(a)

82,739‌

1,962,569‌

CVR

Energy,

Inc.

22,174‌

790,725‌

Evolution

Petroleum

Corp.

11,339‌

69,621‌

Granite

Ridge

Resources,

Inc.

19,138‌

124,397‌

Gulfport

Energy

Corp.

(a)

4,743‌

759,449‌

Matador

Resources

Co.

37,538‌

2,506,412‌

Par

Pacific

Holdings,

Inc.

(a)

20,589‌

763,028‌

PBF

Energy,

Inc.,

Class

A

57,443‌

3,306,994‌

Permian

Resources

Corp.

251,394‌

4,439,618‌

SM

Energy

Co.

38,998‌

1,944,050‌

Vitesse

Energy,

Inc.

7,583‌

179,945‌

Weatherford

International

PLC

(a)

25,828‌

2,981,068‌

$

23,192,960‌

Oil

&

Gas

Services

-

1

.17

%

ChampionX

Corp.

48,738‌

1,749,207‌

Helix

Energy

Solutions

Group,

Inc.

(a)

57,064‌

618,574‌

Liberty

Energy,

Inc.

74,132‌

1,536,015‌

Newpark

Resources,

Inc.

(a)

25,528‌

184,312‌

Tidewater,

Inc.

(a)

21,982‌

2,022,344‌

$

6,110,452‌

Packaging

&

Containers

-

0

.13

%

Greif,

Inc.,

Class

A

6,689‌

461,875‌

Pactiv

Evergreen,

Inc.

14,556‌

208,442‌

$

670,317‌

Pharmaceuticals

-

2

.88

%

Alkermes

PLC

(a)

90,592‌

2,452,325‌

Amneal

Pharmaceuticals,

Inc.

(a)

63,700‌

386,022‌

Amphastar

Pharmaceuticals,

Inc.

(a)

23,772‌

1,043,829‌

BellRing

Brands,

Inc.

(a)

37,362‌

2,205,479‌

Catalyst

Pharmaceuticals,

Inc.

(a)

67,399‌

1,074,340‌

Collegium

Pharmaceutical,

Inc.

(a)

16,021‌

621,935‌

Corcept

Therapeutics,

Inc.

(a)

54,623‌

1,375,953‌

Harmony

Biosciences

Holdings,

Inc.

(a)

21,178‌

711,157‌

Ironwood

Pharmaceuticals,

Inc.

(a)

90,215‌

785,773‌

Option

Care

Health,

Inc.

(a)

71,421‌

2,395,460‌

Pacira

BioSciences,

Inc.

(a)

23,634‌

690,586‌

PetIQ,

Inc.

(a)

13,509‌

246,945‌

Phibro

Animal

Health

Corp.,

Class

A

9,183‌

118,736‌

Prestige

Consumer

Healthcare,

Inc.

(a)

11,650‌

845,324‌

Xeris

Biopharma

Holdings,

Inc.

(a)

46,296‌

102,314‌

$

15,056,178‌

Real

Estate

-

0

.28

%

McGrath

RentCorp

5,836‌

719,987‌

RMR

Group,

Inc.,

Class

A

4,887‌

117,288‌

St.

Joe

Co.

10,596‌

614,250‌

$

1,451,525‌

REITs

-

5

.45

%

Acadia

Realty

Trust

49,721‌

845,754‌

Alexander's,

Inc.

634‌

137,667‌

American

Assets

Trust,

Inc.

21,551‌

472,182‌

Apple

Hospitality

REIT,

Inc.

138,771‌

2,273,069‌

Armada

Hoffler

Properties,

Inc.

20,051‌

208,530‌

Broadstone

Net

Lease,

Inc.

66,276‌

1,038,545‌

CareTrust

REIT,

Inc.

81,547‌

1,987,300‌

CBL

&

Associates

Properties,

Inc.

4,784‌

109,601‌

Centerspace

4,316‌

246,616‌

DiamondRock

Hospitality

Co.

105,058‌

1,009,607‌

COMMON

STOCKS

(continued)

Shares

Held

Value

REITs

(continued)

Empire

State

Realty

Trust,

Inc.,

Class

A

71,333‌

$

722,603‌

Essential

Properties

Realty

Trust,

Inc.

79,703‌

2,124,882‌

Four

Corners

Property

Trust,

Inc.

36,122‌

883,905‌

Franklin

BSP

Realty

Trust,

Inc.

30,118‌

402,377‌

Global

Medical

REIT,

Inc.

21,070‌

184,363‌

Hudson

Pacific

Properties,

Inc.

144,594‌

932,631‌

Innovative

Industrial

Properties,

Inc.

15,504‌

1,605,284‌

Kite

Realty

Group

Trust

116,053‌

2,516,029‌

KKR

Real

Estate

Finance

Trust,

Inc.

43,899‌

441,624‌

NexPoint

Residential

Trust,

Inc.

8,326‌

268,014‌

Piedmont

Office

Realty

Trust,

Inc.,

Class

A

60,929‌

428,331‌

Ryman

Hospitality

Properties,

Inc.

25,210‌

2,914,528‌

Service

Properties

Trust

49,741‌

337,244‌

SITE

Centers

Corp.

130,950‌

1,918,418‌

Tanger,

Inc.

48,477‌

1,431,526‌

Terreno

Realty

Corp.

33,169‌

2,202,422‌

Uniti

Group,

Inc.

94,462‌

557,326‌

Universal

Health

Realty

Income

Trust

2,995‌

109,947‌

Whitestone

REIT

18,052‌

226,553‌

$

28,536,878‌

Retail

-

5

.92

%

Academy

Sports

&

Outdoors,

Inc.

49,937‌

3,372,745‌

Beacon

Roofing

Supply,

Inc.

(a)

39,572‌

3,878,847‌

Bloomin'

Brands,

Inc.

43,211‌

1,239,291‌

BlueLinx

Holdings,

Inc.

(a)

4,525‌

589,336‌

Boot

Barn

Holdings,

Inc.

(a)

32,250‌

3,068,588‌

Buckle,

Inc.

18,685‌

752,445‌

Build-A-Bear

Workshop,

Inc.

10,990‌

328,271‌

Carrols

Restaurant

Group,

Inc.

28,233‌

268,496‌

Chuy's

Holdings,

Inc.

(a)

4,282‌

144,432‌

Dillard's,

Inc.,

Class

A

(c)

3,813‌

1,798,363‌

FirstCash

Holdings,

Inc.

18,286‌

2,332,196‌

GMS,

Inc.

(a)

15,469‌

1,505,752‌

Group

1

Automotive,

Inc.

5,050‌

1,475,762‌

Guess?,

Inc.

33,850‌

1,065,260‌

Hibbett,

Inc.

8,310‌

638,291‌

Jack

in

the

Box,

Inc.

13,616‌

932,424‌

La-Z-Boy,

Inc.

12,874‌

484,320‌

Patrick

Industries,

Inc.

4,334‌

517,783‌

PC

Connection,

Inc.

6,422‌

423,402‌

PriceSmart,

Inc.

4,891‌

410,844‌

Shoe

Carnival,

Inc.

7,329‌

268,535‌

Signet

Jewelers

Ltd.

24,032‌

2,404,882‌

Urban

Outfitters,

Inc.

(a)

60,112‌

2,610,063‌

Vera

Bradley,

Inc.

(a)

11,864‌

80,675‌

Winmark

Corp.

1,118‌

404,381‌

$

30,995,384‌

Savings

&

Loans

-

0

.32

%

OceanFirst

Financial

Corp.

26,268‌

431,058‌

WSFS

Financial

Corp.

26,997‌

1,218,644‌

$

1,649,702‌

Semiconductors

-

3

.19

%

ACM

Research,

Inc.,

Class

A

(a)

57,499‌

1,675,521‌

Amkor

Technology,

Inc.

40,594‌

1,308,751‌

Axcelis

Technologies,

Inc.

(a)

26,338‌

2,937,214‌

Diodes,

Inc.

(a)

19,377‌

1,366,079‌

MACOM

Technology

Solutions

Holdings,

Inc.

(a)

21,230‌

2,030,437‌

Onto

Innovation,

Inc.

(a)

14,781‌

2,676,543‌

Photronics,

Inc.

(a)

26,219‌

742,522‌

Rambus,

Inc.

(a)

50,327‌

3,110,712‌

Veeco

Instruments,

Inc.

(a)

23,420‌

823,681‌

$

16,671,460‌

Software

-

4

.13

%

8x8,

Inc.

(a)

148,921‌

402,087‌

ACI

Worldwide,

Inc.

(a)

35,434‌

1,176,763‌

Adeia,

Inc.

37,774‌

412,492‌

Agilysys,

Inc.

(a)

10,237‌

862,570‌

Altair

Engineering,

Inc.,

Class

A

(a)

16,975‌

1,462,396‌

AvePoint,

Inc.

(a)

60,723‌

480,926‌

Blackbaud,

Inc.

(a)

11,307‌

838,301‌

27

Schedule

of

Investments

Principal

U.S.

Small-Cap

ETF

March

31,

2024

(unaudited)

See

accompanying

notes.

COMMON

STOCKS

(continued)

Shares

Held

Value

Software

(continued)

Box,

Inc.,

Class

A

(a)

65,221‌

$

1,847,059‌

CommVault

Systems,

Inc.

(a)

11,139‌

1,129,829‌

Definitive

Healthcare

Corp.

(a)

30,239‌

244,029‌

Digi

International,

Inc.

(a)

16,449‌

525,217‌

DigitalOcean

Holdings,

Inc.

(a)

42,420‌

1,619,596‌

Donnelley

Financial

Solutions,

Inc.

(a)

13,945‌

864,729‌

Enfusion,

Inc.,

Class

A

(a)

43,595‌

403,254‌

Everbridge,

Inc.

(a)

25,438‌

886,005‌

Health

Catalyst,

Inc.

(a)

20,545‌

154,704‌

Immersion

Corp.

47,556‌

355,719‌

N-able,

Inc.

(a)

33,937‌

443,557‌

PowerSchool

Holdings,

Inc.,

Class

A

(a)

30,301‌

645,108‌

Privia

Health

Group,

Inc.

(a)

40,687‌

797,058‌

Progress

Software

Corp.

16,074‌

856,905‌

PubMatic,

Inc.,

Class

A

(a)

21,430‌

508,320‌

Sapiens

International

Corp.

NV

13,310‌

428,050‌

Simulations

Plus,

Inc.

4,910‌

202,046‌

SPS

Commerce,

Inc.

(a)

7,163‌

1,324,439‌

Verra

Mobility

Corp.

(a)

70,051‌

1,749,173‌

Vimeo,

Inc.

(a)

57,105‌

233,559‌

Weave

Communications,

Inc.

(a)

28,190‌

323,621‌

Yext,

Inc.

(a)

69,270‌

417,698‌

$

21,595,210‌

Telecommunications

-

0

.77

%

Extreme

Networks,

Inc.

(a)

111,695‌

1,288,960‌

Globalstar,

Inc.

(a)

320,594‌

471,273‌

IDT

Corp.,

Class

B

4,721‌

178,501‌

InterDigital,

Inc.

17,211‌

1,832,283‌

Preformed

Line

Products

Co.

1,044‌

134,332‌

Spok

Holdings,

Inc.

8,616‌

137,425‌

$

4,042,774‌

Toys,

Games

&

Hobbies

-

0

.03

%

JAKKS

Pacific,

Inc.

(a)

5,774‌

142,618‌

Transportation

-

2

.48

%

ArcBest

Corp.

15,719‌

2,239,957‌

Ardmore

Shipping

Corp.

18,120‌

297,530‌

Costamare,

Inc.

34,683‌

393,652‌

Covenant

Logistics

Group,

Inc.

2,988‌

138,524‌

DHT

Holdings,

Inc.

59,535‌

684,652‌

Dorian

LPG

Ltd.

37,181‌

1,429,981‌

Forward

Air

Corp.

34,689‌

1,079,175‌

International

Seaways,

Inc.

15,264‌

812,045‌

Matson,

Inc.

16,217‌

1,822,791‌

Nordic

American

Tankers

Ltd.

94,909‌

372,043‌

Overseas

Shipholding

Group,

Inc.,

Class

A

11,128‌

71,219‌

Pangaea

Logistics

Solutions

Ltd.

18,277‌

127,391‌

Safe

Bulkers,

Inc.

51,098‌

253,446‌

Scorpio

Tankers,

Inc.

30,418‌

2,176,408‌

COMMON

STOCKS

(continued)

Shares

Held

Value

Transportation

(continued)

Teekay

Corp.

(a)

14,913‌

$

108,567‌

Teekay

Tankers

Ltd.,

Class

A

11,186‌

653,374‌

World

Kinect

Corp.

12,688‌

335,598‌

$

12,996,353‌

Water

-

0

.22

%

Consolidated

Water

Co.

Ltd.

13,496‌

395,568‌

SJW

Group

12,989‌

735,047‌

$

1,130,615‌

TOTAL

COMMON

STOCKS

a

$

520,801,800‌

INVESTMENT

COMPANIES

-

0

.58

%

Shares

Held

Value

Money

Market

Funds

-

0

.58

%

-

—

Principal

Government

Money

Market

Fund,

Class

R-6

5.22%

(d),(e),(f)

875,775‌

$

875,775‌

State

Street

Institutional

U.S.

Government

Money

Market

Fund,

Premier

Class

5.26%

(d)

2,145,163‌

2,145,163‌

TOTAL

INVESTMENT

COMPANIES

a

$

3,020,938‌

Total

Investments

$

523,822,738‌

Other

Assets

and

Liabilities

-

(0.12%)

(

633,525‌

)

TOTAL

NET

ASSETS

-

100.00%

$

523,189,213‌

(a)

Non-income

producing

security.

(b)

The

value

of

these

investments

was

determined

using

significant

unobservable

inputs,

in

good

faith

by

the

Advisor,

under

procedures

established

and

periodically

reviewed

by

the

Board

of

Trustees.

(c)

Security

or

a

portion

of

the

security

was

on

loan.

At

the

end

of

the

period,

the

value

of

these

securities

totaled

$869,890

or

0.17%

of

net

assets.

(d)

1-day

yield

shown

as

of

period

end.

(e)

Affiliated

Security.

Security

is

either

an

affiliate

(and

registered

under

the

Investment

Company

Act

of

1940)

or

an

affiliate

as

defined

by

the

Investment

Company

Act

of

1940

(controls

5.00%

or

more

of

the

outstanding

voting

shares

of

the

security).

Please

see

Affiliated

Securities

sub-schedule

for

transactional

information.

(f)

Security

or

a

portion

of

the

security

was

received

as

collateral

for

securities

lending.

At

the

end

of

the

period,

the

value

of

these

securities

totaled

$875,775

or

0.17%

of

net

assets.

Portfolio

Summary

Sector

Percent

Consumer,

Non-cyclical

22.12%

Financial

20.17%

Industrial

17.14%

Consumer,

Cyclical

12.35%

Technology

11.64%

Energy

7.64%

Communications

3.42%

Utilities

2.54%

Basic

Materials

2.45%

Money

Market

Funds

0.58%

Government

0.07%

Other

Assets

and

Liabilities

(0.12)%

TOTAL

NET

ASSETS

100.00%

Affiliated

Securities

June

30,

2023

Value

Purchases

Cost

Sales

Proceeds

March

31,

2024

Value

Principal

Government

Money

Market

Fund,

Class

R-6

5.22%

$

847,907‌

$

10,941,271‌

$

10,913,403‌

$

875,775‌

$

847,907‌

$

10,941,271‌

$

10,913,403‌

$

875,775‌

a

a

Income

(a)

Realized

Gain/(Loss)

on

Investments

Realized

Gain

from

Capital

Gain

Distributions

Change

in

Unrealized

Gain/(Loss)

Principal

Government

Money

Market

Fund,

Class

R-6

5.22%

$

—‌

$

—‌

$

—‌

$

—‌

$

—‌

$

—‌

$

—‌

$

—‌

(a)

Amount

excludes

earnings

from

securities

lending

collateral.

28

Schedule

of

Investments

Principal

Value

ETF

March

31,

2024

(unaudited)

See

accompanying

notes.

COMMON

STOCKS

-

99

.46

%

Shares

Held

Value

Aerospace

&

Defense

-

1

.61

%

-

—

L3Harris

Technologies,

Inc.

2,179‌

$

464,345‌

Lockheed

Martin

Corp.

1,125‌

511,729‌

$

976,074‌

Agriculture

-

1

.29

%

Altria

Group,

Inc.

10,706‌

466,996‌

Archer-Daniels-Midland

Co.

5,015‌

314,992‌

$

781,988‌

Apparel

-

0

.83

%

Tapestry,

Inc.

10,556‌

501,199‌

Auto

Manufacturers

-

1

.01

%

PACCAR,

Inc.

4,928‌

610,530‌

Banks

-

10

.44

%

Bank

of

America

Corp.

21,529‌

816,380‌

Bank

of

New

York

Mellon

Corp.

8,830‌

508,785‌

Citizens

Financial

Group,

Inc.

12,383‌

449,379‌

Comerica,

Inc.

7,077‌

389,164‌

Fifth

Third

Bancorp

13,888‌

516,772‌

KeyCorp

32,396‌

512,181‌

M&T

Bank

Corp.

2,910‌

423,230‌

Northern

Trust

Corp.

4,792‌

426,105‌

PNC

Financial

Services

Group,

Inc.

3,337‌

539,259‌

Regions

Financial

Corp.

18,757‌

394,647‌

State

Street

Corp.

5,349‌

413,585‌

Truist

Financial

Corp.

13,226‌

515,549‌

Zions

Bancorp

NA

9,592‌

416,293‌

$

6,321,329‌

Building

Materials

-

1

.60

%

Johnson

Controls

International

PLC

7,028‌

459,069‌

Masco

Corp.

6,447‌

508,539‌

$

967,608‌

Chemicals

-

2

.41

%

CF

Industries

Holdings,

Inc.

4,774‌

397,244‌

Linde

PLC

1,651‌

766,592‌

Mosaic

Co.

9,086‌

294,932‌

$

1,458,768‌

Commercial

Services

-

1

.46

%

Automatic

Data

Processing,

Inc.

2,001‌

499,730‌

Robert

Half,

Inc.

4,864‌

385,618‌

$

885,348‌

Computers

-

5

.97

%

Accenture

PLC,

Class

A

2,079‌

720,602‌

Apple,

Inc.

12,218‌

2,095,143‌

Cognizant

Technology

Solutions

Corp.,

Class

A

5,853‌

428,967‌

HP,

Inc.

12,197‌

368,593‌

$

3,613,305‌

Distribution

&

Wholesale

-

0

.68

%

Pool

Corp.

1,014‌

409,149‌

Diversified

Financial

Services

-

4

.77

%

Ameriprise

Financial,

Inc.

1,187‌

520,428‌

Discover

Financial

Services

3,824‌

501,288‌

Franklin

Resources,

Inc.

13,273‌

373,104‌

Intercontinental

Exchange,

Inc.

3,988‌

548,071‌

Nasdaq,

Inc.

7,532‌

475,269‌

Synchrony

Financial

10,941‌

471,776‌

$

2,889,936‌

Electronics

-

0

.74

%

Allegion

PLC

3,350‌

451,278‌

Environmental

Control

-

0

.86

%

Republic

Services,

Inc.

2,726‌

521,865‌

Food

-

2

.63

%

Conagra

Brands,

Inc.

12,164‌

360,541‌

General

Mills,

Inc.

5,786‌

404,846‌

Hershey

Co.

1,815‌

353,018‌

Kroger

Co.

8,262‌

472,008‌

$

1,590,413‌

Hand

&

Machine

Tools

-

0

.69

%

Snap-on,

Inc.

1,402‌

415,300‌

Healthcare

-

Products

-

1

.64

%

Abbott

Laboratories

5,936‌

674,686‌

COMMON

STOCKS

(continued)

Shares

Held

Value

Healthcare

-

Products

(continued)

Dentsply

Sirona,

Inc.

9,552‌

$

317,031‌

$

991,717‌

Healthcare

-

Services

-

0

.62

%

Quest

Diagnostics,

Inc.

2,820‌

375,370‌

Home

Builders

-

0

.93

%

PulteGroup,

Inc.

4,652‌

561,124‌

Household

Products

&

Wares

-

0

.76

%

Avery

Dennison

Corp.

2,058‌

459,449‌

Insurance

-

7

.24

%

Allstate

Corp.

3,668‌

634,601‌

American

International

Group,

Inc.

6,967‌

544,610‌

Chubb

Ltd.

2,389‌

619,062‌

Cincinnati

Financial

Corp.

3,562‌

442,293‌

Hartford

Financial

Services

Group,

Inc.

5,317‌

547,917‌

Marsh

&

McLennan

Cos.,

Inc.

2,604‌

536,372‌

MetLife,

Inc.

6,562‌

486,310‌

Travelers

Cos.,

Inc.

2,478‌

570,287‌

$

4,381,452‌

Internet

-

0

.36

%

Amazon.com,

Inc.

(a)

1,216‌

219,342‌

Iron

&

Steel

-

0

.92

%

Steel

Dynamics,

Inc.

3,740‌

554,380‌

Machinery

-

Construction

&

Mining

-

1

.22

%

Caterpillar,

Inc.

2,014‌

737,990‌

Media

-

2

.08

%

Comcast

Corp.,

Class

A

13,845‌

600,181‌

Fox

Corp.,

Class

A

10,763‌

336,559‌

Fox

Corp.,

Class

B

11,260‌

322,261‌

$

1,259,001‌

Miscellaneous

Manufacturers

-

1

.74

%

A

O

Smith

Corp.

5,211‌

466,176‌

Parker-Hannifin

Corp.

1,055‌

586,359‌

$

1,052,535‌

Oil

&

Gas

-

8

.36

%

APA

Corp.

8,440‌

290,167‌

Chevron

Corp.

4,776‌

753,366‌

Devon

Energy

Corp.

8,044‌

403,648‌

EQT

Corp.

8,853‌

328,181‌

Exxon

Mobil

Corp.

9,049‌

1,051,856‌

Marathon

Petroleum

Corp.

3,033‌

611,150‌

Phillips

66

3,770‌

615,792‌

Pioneer

Natural

Resources

Co.

1,843‌

483,787‌

Valero

Energy

Corp.

3,083‌

526,237‌

$

5,064,184‌

Packaging

&

Containers

-

1

.68

%

Packaging

Corp.

of

America

2,516‌

477,487‌

Westrock

Co.

10,972‌

542,565‌

$

1,020,052‌

Pharmaceuticals

-

3

.35

%

Bristol-Myers

Squibb

Co.

8,830‌

478,851‌

Cencora,

Inc.

2,145‌

521,213‌

CVS

Health

Corp.

6,635‌

529,208‌

Pfizer,

Inc.

17,979‌

498,917‌

$

2,028,189‌

Pipelines

-

0

.76

%

Williams

Cos.,

Inc.

11,892‌

463,431‌

REITs

-

7

.71

%

Alexandria

Real

Estate

Equities,

Inc.

3,166‌

408,129‌

Essex

Property

Trust,

Inc.

1,554‌

380,435‌

Extra

Space

Storage,

Inc.

3,041‌

447,027‌

Host

Hotels

&

Resorts,

Inc.

23,063‌

476,943‌

Invitation

Homes,

Inc.

11,175‌

397,942‌

Kimco

Realty

Corp.

18,516‌

363,099‌

Mid-America

Apartment

Communities,

Inc.

2,654‌

349,213‌

Prologis,

Inc.

4,269‌

555,909‌

Simon

Property

Group,

Inc.

3,488‌

545,837‌

UDR,

Inc.

9,488‌

354,946‌

VICI

Properties,

Inc.

13,057‌

388,968‌

$

4,668,448‌

29

Schedule

of

Investments

Principal

Value

ETF

March

31,

2024

(unaudited)

See

accompanying

notes.

COMMON

STOCKS

(continued)

Shares

Held

Value

Retail

-

4

.60

%

Best

Buy

Co.,

Inc.

4,801‌

$

393,826‌

Darden

Restaurants,

Inc.

2,405‌

401,996‌

Genuine

Parts

Co.

2,473‌

383,142‌

Home

Depot,

Inc.

2,548‌

977,413‌

Lowe's

Cos.,

Inc.

2,481‌

631,985‌

$

2,788,362‌

Semiconductors

-

6

.89

%

Analog

Devices,

Inc.

2,710‌

536,011‌

Broadcom,

Inc.

1,035‌

1,371,800‌

Microchip

Technology,

Inc.

5,175‌

464,249‌

QUALCOMM,

Inc.

4,757‌

805,360‌

Skyworks

Solutions,

Inc.

3,574‌

387,136‌

Texas

Instruments,

Inc.

3,492‌

608,341‌

$

4,172,897‌

Software

-

5

.52

%

Fidelity

National

Information

Services,

Inc.

7,225‌

535,951‌

Microsoft

Corp.

5,684‌

2,391,372‌

Paychex,

Inc.

3,358‌

412,362‌

$

3,339,685‌

Telecommunications

-

0

.66

%

Corning,

Inc.

12,174‌

401,255‌

Transportation

-

5

.43

%

CH

Robinson

Worldwide,

Inc.

3,938‌

299,839‌

CSX

Corp.

14,586‌

540,703‌

Expeditors

International

of

Washington,

Inc.

3,286‌

399,479‌

FedEx

Corp.

1,673‌

484,735‌

Norfolk

Southern

Corp.

1,989‌

506,937‌

COMMON

STOCKS

(continued)

Shares

Held

Value

Transportation

(continued)

Union

Pacific

Corp.

2,460‌

$

604,988‌

United

Parcel

Service,

Inc.,

Class

B

3,053‌

453,767‌

$

3,290,448‌

TOTAL

COMMON

STOCKS

a

$

60,223,401‌

INVESTMENT

COMPANIES

-

0

.32

%

Shares

Held

Value

Money

Market

Funds

-

0

.32

%

-

—

State

Street

Institutional

U.S.

Government

Money

Market

Fund,

Premier

Class

5.26%

(b)

195,970‌

$

195,970‌

TOTAL

INVESTMENT

COMPANIES

a

$

195,970‌

Total

Investments

$

60,419,371‌

Other

Assets

and

Liabilities

-

0.22%

131,630‌

TOTAL

NET

ASSETS

-

100.00%

$

60,551,001‌

(a)

Non-income

producing

security.

(b)

1-day

yield

shown

as

of

period

end.

Portfolio

Summary

Sector

Percent

Financial

30.16%

Technology

18.38%

Industrial

15.57%

Consumer,

Non-cyclical

11.75%

Energy

9.12%

Consumer,

Cyclical

8.05%

Basic

Materials

3.33%

Communications

3.10%

Money

Market

Funds

0.32%

Other

Assets

and

Liabilities

0.22%

TOTAL

NET

ASSETS

100.00%

30

Principal

Exchange-Traded

Funds

March

31,

2024

(unaudited)

1.

Security

Valuation

The

Funds

may

invest

in

series

of

Principal

Funds,

Inc.

and

other

investment

funds,

which

may

include

money

market

funds

and

other

registered

open-end

investment

companies.

Investments

in

registered

open-end

investment

companies

are

valued

at

the

respective

fund’s

closing

net

asset

value

(“NAV”)

per

share

on

the

day

of

valuation.

The

Funds

value

securities

for

which

market

quotations

are

readily

available

at

fair

value,

which

is

determined

using

the

last

reported

sale

price.

If

no

sales

are

reported,

as

is

regularly

the

case

for

some

securities

traded

over-the-counter

(“OTC”),

securities

are

valued

using

the

last

reported

bid

price

or

an

evaluated

bid

price

provided

by

a

pricing

service.

Pricing

services

use

modeling

techniques

that

incorporate

security

characteristics

such

as

current

quotations

by

broker/dealers,

coupon,

maturity,

quality,

type

of

issue,

trading

characteristics,

other

yield

and

risk

factors

and

other

market

conditions

to

determine

an

evaluated

bid

price.

When

reliable

market

quotations

are

not

considered

to

be

readily

available,

which

may

be

the

case,

for

example,

with

respect

to

restricted

securities,

certain

debt

securities,

preferred

stocks,

and

foreign

securities,

the

investments

are

valued

at

their

fair

value

as

determined

in

good

faith

by

the

Principal

Global

Investors,

LLC

(“the

Advisor”)

under

procedures

established

and

periodically

reviewed

by

the

Board

of

Trustees.

The

value

of

foreign

securities

used

in

computing

the

NAV

per

share

is

generally

determined

as

of

the

close

of

the

foreign

exchange

where

the

security

is

principally

traded.

Events

that

occur

after

the

close

of

the

applicable

foreign

market

or

exchange

but

prior

to

the

calculation

of

the

Fund’s

NAV

are

reflected

in

the

Fund’s

NAV

and

these

securities

are

valued

at

fair

value.

Many

factors,

provided

by

independent

pricing

services,

are

reviewed

in

the

course

of

making

a

good

faith

determination

of

a

security’s

fair

value

including,

but

not

limited

to,

price

movements

in

American

Depository

Receipts

(“ADRs”),

futures

contracts,

industry

indices,

general

indices,

and

foreign

currencies.

To

the

extent

the

Funds

invest

in

foreign

securities

listed

on

foreign

exchanges

which

trade

on

days

on

which

the

Funds

do

not

determine

NAV,

for

example,

weekends

and

other

customary

national

U.S.

holidays,

the

Fund’s

NAV

could

be

significantly

affected

on

days

when

shares

are

not

able

to

be

issued

or

redeemed

by

Authorized

Participants

(“APs”).

Certain

securities

issued

by

companies

in

emerging

market

countries

may

have

more

than

one

quoted

valuation

at

any

given

point

in

time,

sometimes

referred

to

as

a

“local”

price

and

a

“premium”

price.

The

premium

price

is

often

a

negotiated

price,

which

may

not

consistently

represent

a

price

at

which

a

specific

transaction

can

be

effected.

It

is

the

policy

of

the

Funds

to

value

such

securities

at

prices

at

which

it

is

expected

those

shares

may

be

sold,

and

the

Advisor,

or

any

sub-advisor,

is

authorized

to

make

such

determinations

subject

to

such

oversight

by

the

Board

of

Trustees,

as

may

occasionally

be

necessary.

2.

Fair

Valuation

Fair

value

is

defined

as

the

price

that

the

Funds

would

receive

upon

selling

a

security

or

transferring

a

liability

in

a

timely

transaction

to

an

independent

buyer

in

the

principal

or

most

advantageous

market

of

the

security

at

the

measurement

date.

In

determining

fair

value,

the

Funds

may

use

one

or

more

of

the

following

approaches:

market,

income

and/or

cost.

A

hierarchy

for

inputs

is

used

in

measuring

fair

value

that

maximizes

the

use

of

observable

inputs

and

minimizes

the

use

of

unobservable

inputs

by

requiring

that

the

most

observable

inputs

be

used

when

available.

Observable

inputs

are

inputs

that

reflect

the

assumptions

market

participants

would

use

in

pricing

the

asset

or

liability

developed

based

on

market

data

obtained

from

sources

independent

of

the

Funds.

Unobservable

inputs

are

inputs

that

reflect

the

Fund’s

own

estimates

about

the

estimates

market

participants

would

use

in

pricing

the

asset

or

liability

developed

based

on

the

best

information

available

in

the

circumstances.

The

three-tier

hierarchy

of

inputs

is

summarized

in

the

three

broad

levels

listed

below.

Level

1

—

Quoted

prices

are

available

in

active

markets

for

identical

securities

as

of

the

reporting

date.

Investments

which

are

generally

included

in

this

category

include

listed

equities

and

listed

derivatives.

Level

2

—

Other

significant

observable

inputs

(including

quoted

prices

for

similar

investments,

interest

rates,

prepayment

speeds,

credit

risk,

etc.).

Investments

which

are

generally

included

in

this

category

include

certain

corporate

bonds,

senior

floating

rate

interests,

OTC

derivatives,

mortgage-

backed

securities

and

municipal

bonds.

Level

3

—

Significant

unobservable

inputs

(including

the

Funds’

assumptions

in

determining

the

fair

value

of

investments).

Investments

which

are

generally

included

in

this

category

include

certain

corporate

bonds

and

certain

common

stocks.

31

Principal

Exchange-Traded

Funds

March

31,

2024

(unaudited)

The

availability

of

observable

inputs

can

vary

from

security

to

security

and

is

affected

by

a

wide

variety

of

factors,

including,

for

example,

the

type

of

security,

whether

the

security

is

new

and

not

yet

established

in

the

market

place,

and

other

characteristics

particular

to

the

transaction.

To

the

extent

that

valuation

is

based

on

models

or

inputs

that

are

less

observable

or

unobservable

in

the

market,

the

determination

of

fair

value

requires

more

judgment.

Accordingly,

the

degree

of

judgment

exercised

by

the

Funds

in

determining

fair

value

is

greatest

for

instruments

categorized

in

Level

3.

In

certain

cases,

the

inputs

used

to

measure

fair

value

may

fall

into

different

levels

of

the

fair

value

hierarchy.

In

such

cases,

for

disclosure

purposes,

the

level

in

the

fair

value

hierarchy

within

which

the

fair

value

measurement

in

its

entirety

falls

is

determined

based

on

the

lowest

level

input

that

is

significant

to

the

fair

value

measurement

in

its

entirety.

Fair

value

is

a

market

based

measure

considered

from

the

perspective

of

a

market

participant

who

holds

the

asset

rather

than

an

entity

specific

measure.

Therefore,

even

when

market

assumptions

are

not

readily

available,

the

Funds’

own

assumptions

are

set

to

reflect

those

that

market

participants

would

use

in

pricing

the

asset

or

liability

at

the

measurement

date.

The

Funds

use

prices

and

inputs

that

are

current

as

of

the

measurement

date,

to

the

extent

available.

Investments

which

are

included

in

the

Level

3

category

may

be

valued

using

quoted

prices

from

brokers

and

dealers

participating

in

the

market

for

these

investments.

These

investments

are

classified

as

Level

3

investments

due

to

the

lack

of

market

transparency

and

market

corroboration

to

support

these

quoted

prices.

Valuation

models

may

be

used

as

the

pricing

source

for

other

investments

classified

as

Level

3.

Valuation

models

rely

on

one

or

more

significant

unobservable

inputs

such

as

prepayment

rates,

probability

of

default,

or

loss

severity

in

the

event

of

default.

Significant

increases

in

any

of

those

inputs

in

isolation

would

result

in

a

significantly

lower

fair

value

measurement.

The

fair

values

of

these

entities

are

dependent

on

economic,

political

and

other

considerations.

The

values

of

the

underlying

investee

entities

may

be

affected

by

significant

changes

in

the

economic

conditions,

changes

in

government

policies,

and

other

factors

(e.g.,

natural

disasters,

pandemics,

accidents,

conflicts,

etc.).

The

inputs

or

methodology

used

for

valuing

securities

are

not

necessarily

an

indication

of

the

risk

associated

with

investing

in

those

instruments.

During

the

period

there

were

no

significant

purchases,

sales,

or

transfers

into

or

out

of

Level

3.

The

following

is

a

summary

of

the

inputs

used

as

of

March

31,

2024,

in

valuing

the

Funds’

securities

carried

at

fair

value:

Fund

Level

1

-

Quoted

Prices

Level

2

-

Other

Significant

Observable

Inputs

Level

3

-

Significant

Unobservable

Inputs

Totals

(Level

1,2,3)

Principal

Active

High

Yield

ETF

Bonds

*

$

—

$

147,960,853

$

—

$

147,960,853

Senior

Floating

Rate

Interests

*

—

9,557,580

—

9,557,580

U.S.

Government

&

Government

Agency

Obligations

*

—

1,535,766

—

1,535,766

Investment

Companies

*

14,024,102

—

—

14,024,102

Total

investments

in

securities

$

14,024,102

$

159,054,199

$

—

$

173,078,301

Principal

Focused

Blue

Chip

ETF

Common

Stocks

*

38,067,867

—

—

38,067,867

Investment

Companies

*

5,611

—

—

5,611

Total

investments

in

securities

$

38,073,478

$

—

$

—

$

38,073,478

Principal

Healthcare

Innovators

ETF

Common

Stocks

*

Basic

Materials

45,342

—

—

45,342

Consumer,

Non-cyclical

44,357,785

—

3,797

44,361,582

Industrial

111,634

—

—

111,634

Technology

13,142

—

—

13,142

Investment

Companies

*

1,212,090

—

—

1,212,090

Total

investments

in

securities

$

45,739,993

$

—

$

3,797

$

45,743,790

Principal

Investment

Grade

Corporate

Active

ETF

Bonds

*

—

76,421,779

—

76,421,779

Investment

Companies

*

1,041,151

—

—

1,041,151

Total

investments

in

securities

$

1,041,151

$

76,421,779

$

—

$

77,462,930

2.

Fair

Valuation

(continued)

32

Principal

Exchange-Traded

Funds

March

31,

2024

(unaudited)

The

Funds’

Schedules

of

Investments

for

the

period

ended

March

31,

2024 has

not

been

audited.

This

report

is

provided

for

the

general

information

of

the

Funds’

shareholders.

For

more

information

regarding

the

Funds

and

their

holdings,

please

see

the

Funds’

prospectus. 

Fund

Level

1

-

Quoted

Prices

Level

2

-

Other

Significant

Observable

Inputs

Level

3

-

Significant

Unobservable

Inputs

Totals

(Level

1,2,3)

Principal

Investment

Grade

Corporate

Active

ETF

(continued)

Derivatives

Assets

Interest

Rate

Contracts

Futures

$

32,862

$

—

$

—

$

32,862

Derivatives

Liabilities

Interest

Rate

Contracts

Futures

(

6,795

)

—

—

(

6,795

)

Principal

Quality

ETF

Common

Stocks

*

48,651,584

—

—

48,651,584

Investment

Companies

*

94,330

—

—

94,330

Total

investments

in

securities

$

48,745,914

$

—

$

—

$

48,745,914

Principal

Real

Estate

Active

Opportunities

ETF

Common

Stocks

*

9,272,699

—

—

9,272,699

Investment

Companies

*

115,696

—

—

115,696

Total

investments

in

securities

$

9,388,395

$

—

$

—

$

9,388,395

Principal

Spectrum

Preferred

Securities

Active

ETF

Bonds

*

—

838,793,745

—

838,793,745

Investment

Companies

*

5,886,783

—

—

5,886,783

Total

investments

in

securities

$

5,886,783

$

838,793,745

$

—

$

844,680,528

Principal

Spectrum

Tax-Advantaged

Dividend

Active

ETF

Preferred

Stocks

*

1,797,823

—

—

1,797,823

Bonds

*

—

21,786,532

—

21,786,532

Investment

Companies

*

280,874

—

—

280,874

Total

investments

in

securities

$

2,078,697

$

21,786,532

$

—

$

23,865,229

Principal

U.S.

Mega-Cap

ETF

Common

Stocks

*

2,268,060,123

—

—

2,268,060,123

Investment

Companies

*

5,662,432

—

—

5,662,432

Total

investments

in

securities

$

2,273,722,555

$

—

$

—

$

2,273,722,555

Principal

U.S.

Small-Cap

ETF

Common

Stocks

*

Basic

Materials

12,783,506

—

—

12,783,506

Communications

17,931,625

—

—

17,931,625

Consumer,

Cyclical

64,611,589

—

—

64,611,589

Consumer,

Non-cyclical

115,742,925

—

3,863

115,746,788

Energy

39,994,417

—

—

39,994,417

Financial

105,555,074

—

—

105,555,074

Government

370,546

—

—

370,546

Industrial

89,657,703

—

—

89,657,703

Technology

60,881,064

—

—

60,881,064

Utilities

13,269,488

—

—

13,269,488

Investment

Companies

*

3,020,938

—

—

3,020,938

Total

investments

in

securities

$

523,818,875

$

—

$

3,863

$

523,822,738

Principal

Value

ETF

Common

Stocks

*

60,223,401

—

—

60,223,401

Investment

Companies

*

195,970

—

—

195,970

Total

investments

in

securities

$

60,419,371

$

—

$

—

$

60,419,371

*

For

additional

detail

regarding

sector

and/or

sub-industry

classifications,

please

see

the

Schedules

of

Investments.

2.

Fair

Valuation

(continued)