SEC FORM 3

SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person^*

Xie Lucy

(Last)

(First)

(Middle)

C/O CASA SYSTEMS, INC.

100 OLD RIVER ROAD

(Street)

ANDOVER

01810

(City)

(State)

(Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
12/14/2017

3. Issuer Name and Ticker or Trading Symbol
Casa Systems Inc [ CASA ]

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director	10% Owner
X	Officer (give title below)	Other (specify below)
	SVP of Operations

5. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock	2,433,600⁽¹⁾	D

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
1. Title of Derivative Security (Instr. 4)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
Stock option (right to buy)	⁽²⁾	01/22/2025	Common Stock	227,440	$4.184	D
Stock option (right to buy)	⁽³⁾	03/25/2026	Common Stock	149,645	$8.394	D
Stock option (right to buy)	⁽⁴⁾	01/30/2027	Common Stock	107,790	$12.236	D

Explanation of Responses:

1. Consists of 1,850,000 shares of Common Stock and shares issued and issuable under an aggregate of 583,600 restricted stock units ("RSUs"). Each RSU represents the right to receive one share of common stock upon vesting. The RSUs consist of (1) an award of 341,160 RSUs that vests as to 50% of the original number of RSUs on January 1, 2016, 33% on January 1, 2017 and 17% on January 1, 2018, (2) an award of 113,720 RSUs that vests as to 25% of the original number of RSUs on January 1, 2016, and as to an additional 25% upon the completion of each year thereafter, (3) an award of 74,825 RSUs that vests as to 25% of the original number of RSUs on January 1, 2017, and as to an additional 25% upon the completion of each year thereafter, and (4) an award of 53,895 RSUs that vests as to 25% of the original number of RSUs on January 1, 2018, and as to an additional 25% upon the completion of each year thereafter.

2. This option was granted on January 23, 2015 and vests over four years, with 25% of the original 227,440 shares underlying the option having vested on January 1, 2016, and 2.0833% of the original 227,440 shares vesting monthly thereafter.

3. This option was granted on March 26, 2016 and vests over four years, with 25% of the original 149,645 shares underlying the option having vested on January 1, 2017, and 2.0833% of the original 149,645 shares vesting monthly thereafter.

4. This option was granted on January 31, 2017 and vests over four years, with 25% of the original 107,790 shares underlying the option vesting on January 1, 2018, and 2.0833% of the original 107,790 shares vesting monthly thereafter.

Remarks:

	/s/ Todd Keebaugh, attorney-in-fact	12/14/2017
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 5 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.