GlaxoSmithKline PLC — Major Shareholding Notification 2010

Feb 12, 2010

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UNITED STATES SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

Under the Securities Exchange Act of 1934 (Amendment No. 4)*

MAXYGEN, INC.

(Name of Issuer)

COMMON STOCK

(Title of Class of Securities)

577776107

(CUSIP Number)

December 31, 2009

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

o Rule 13d-1(b)

o Rule 13d-1(c)

þ Rule 13d-1(d)

• The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

This Amendment No. 4 amends and supplements the Statement on Schedule 13G electronically filed with the Securities and Exchange Commission (the “Commission”) on February 11, 2000 and subsequent Amendment Nos. 1, 2 and 3 filed with the Commission on July 20, 2001, February 13, 2004 and February 12, 2008 respectively in connection with ownership of securities of Maxygen Inc. (the “Initial Statement”).

The information required in the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

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CUSIP No. 577776107

1	NAMES OF REPORTING PERSONS GlaxoSmithKline plc
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
	(a) o
	(b) o
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION
	England and Wales
	5	SOLE VOTING POWER
NUMBER OF		1,433,361
SHARES	6	SHARED VOTING POWER
BENEFICIALLY
OWNED BY
EACH	7	SOLE DISPOSITIVE POWER
REPORTING
PERSON		1,433,361
WITH:	8	SHARED DISPOSITIVE POWER
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	1,433,361
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES
	o
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
	3.73%
12	TYPE OF REPORTING PERSON
	CO

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CUSIP No. 577776107

ITEM 1.

(a) Name of Issuer:

(b) Address of Issuer’s Principal Executive Offices:

ITEM 2.

(a) Name of Person Filing:

(b) Address of Principal Business Office, or if None, Residence:

(c) Citizenship:

(d) Title of Class of Securities:

(e) CUSIP Number:

ITEM 3. IF THIS STATEMENT IS FILED PURSUANT TO SS.240.13d- 1(b) OR 240.13d- 2(b) OR (c), CHECK WHETHER THE PERSON FILING IS A:

Not Applicable.

ITEM 4. OWNERSHIP.

Provide the following information regarding the aggregate number and percentage of the class of securities of the issuer identified in Item 1.

The information in items 1 and 5 through 11 on the cover pages (page 2) on Schedule 13G is hereby incorporated by reference.

Folio /Folio

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ITEM 5. OWNERSHIP OF FIVE 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 five percent of the class of securities, check the following [x ].

ITEM 6. OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON.

ITEM 7. IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY.

ITEM 8. IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP.

ITEM 9. NOTICE OF DISSOLUTION OF GROUP.

Folio /Folio

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ITEM 10. CERTIFICATIONS.

(a) The following certification shall be included if the statement is filed pursuant to Rule 13d-1(b):

“By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and 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 such purpose or effect.”

(b) The following certification shall be included if the statement is filed pursuant to Rule 13d-1(c):

“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 such purpose or effect.”

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

February 12, 2010

(Date)

/s/

(Signature)

Victoria A.Whyte, Deputy Company Secretary

(Name/Title)

The original statement shall be signed by each person on whose behalf the statement is filed or his authorized representative. If the statement is signed on behalf of a person by his authorized representative other than an executive officer or general partner of the filing person, evidence of the representative’s authority to sign on behalf of such person shall be filed with the statement, provided, however, that a power of attorney for this purpose which is already on file with the Commission may be incorporated by reference. The name and any title of each person who signs the statement shall be typed or printed beneath his signature.

Folio /Folio