SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

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Rule 13d-1(b)

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Rule 13d-1(c)

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Rule 13d-1(d)

CUSIP No. 98401F105

13G

1.

Names of Reporting Persons
John Stafford, Jr.

2.

Check the Appropriate Box if a Member of a Group (see instructions)

(a)

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(b)

o

3.

SEC USE ONLY

4.

Citizenship or Place of Organization
United States

Number of
Shares
Beneficially
Owned by
Each
Reporting
Person With:

5.

Sole Voting Power
1,642,741

6.

Shared Voting Power

7.

Sole Dispositive Power
1,642,741

8.

Shared Dispositive Power

9.

Aggregate Amount Beneficially Owned by Each Reporting Person
1,642,741

10.

Check if the Aggregate Amount in Row (9) Excludes Certain Shares (see instructions)  o

11.

Percent of Class Represented by Amount in Row 9
5.2%

12.

Type of Reporting Person (see instructions)
IN

Item 1(a).

Name of Issuer:
Xencor, Inc.

Item 1(b).

Address of Issuer’s Principal Executive Offices:
111 West Lemon Avenue, 2nd Floor, Monrovia, CA 91016.

Item 2(a).

Name of Person Filing:
John Stafford, Jr.

Item 2(b).

Address of Principal Business Office or, if none, Residence:
45 N. Green Bay Road, Lake Forest, IL 60045

Item 2(c).

Citizenship:
United States

Item 2(d).

Title of Class of Securities:
Common Stock

Item 2(e).

CUSIP Number:
98401F 105

Item 3.

If this statement is filed pursuant to §§240.13d-1(b), or 240.13d-2(b) or (c), check whether the person filing is a:

(a)

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Broker or dealer registered under Section 15 of the Act (15 U.S.C. 78o);

(b)

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Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);

(c)

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Insurance company as defined in section 3(a)19) of the Act (15 U.S.C. 78c);

(d)

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Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);

(e)

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An investment adviser in accordance with §240.13d-1(b)(1)(ii)(E);

(f)

o

An employee benefit plan or endowment fund in accordance with §240.13d-1(b)(1)(ii)(F);

(g)

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A parent holding company or control person in accordance with §240.13d-1(b)(1)(ii)(G);

(h)

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A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);

(i)

o

A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);

(j)

o

A non-U.S. institution in accordance with §240.13d–1(b)(1)(ii)(J);

(k)

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Group, in accordance with §240.13d–1(b)(1)(ii)(K). If filing as a non-U.S. institution in accordance with §240.13d–1(b)(1)(ii)(J), please specify the type of institution:                                              

Item 4.

Ownership

(a)

Amount Beneficially Owned:   

1,642,741 shares of Common Stock.  This amount includes 90 shares of the Issuers Common Stock held by John Stafford, Jr., 1,367,651 shares of the Issuer’s Common Stock held by JSS, Jr. 2013 XAT, a grantor retained annuity trust for which John Stafford, Jr. is trustee, and 275,000 shares of the Issuer’s Common Stock purchased at the Issuer’s initial public offering and held by John Stafford, Jr.

(b)

Percent of Class:   

5.2%

(c)

Number of shares as to which the person has:

(i)

Sole power to vote or to direct the vote:   

1,642,741

(ii)

Shared power to vote or to direct the vote    

(iii)

Sole power to dispose or to direct the disposition of:   

1,642,741

(iv)

Shared power to dispose or to direct the disposition of   

Item 5.

Ownership of 5 Percent or Less of a Class

If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than 5 percent of the class of securities, check the following  o.

Item 6.

Ownership of More than 5 Percent on Behalf of Another Person

Not Applicable

Item 7.

Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company or Control Person.

Not Applicable

Item 8.

Identification and Classification of Members of the Group

Not Applicable

Item 9.

Notice of Dissolution of a Group

Not Applicable

Item 10.

Certification

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

December 16, 2013

Date:

/s/ John Stafford, Jr.

Signature

John Stafford, Jr.

Name/Title

ATTENTION:

Intentional misstatements or omissions of fact constitute Federal Criminal Violations (See 18 U.S.C. 1001)