SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* TAN LIP BU (Last) (First) (Middle) ONE CALIFORNIA STREET SUITE 2800 (Street) SAN FRANCISCO CA 94111 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol AMBARELLA INC [ AMBA ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X Director 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 10/15/2012
	4. 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 Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Ordinary Shares	10/15/2012		C		3,012,743	A	(1)(2)(3)	3,012,743	I	See Footnote(4)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Series A Convertible Preference Shares	(1)	10/15/2012		C			1,666,665	(1)	(1)	Ordinary Shares	1,666,665	$0	0	I	See Footnote(4)
Series B Convertible Preference Shares	(2)	10/15/2012		C			697,931	(2)	(2)	Ordinary Shares	697,931	$0	0	I	See Footnote(4)
Series C Convertible Preference Shares	(3)	10/15/2012		C			648,147	(3)	(3)	Ordinary Shares	648,147	$0	0	I	See Footnote(4)

Explanation of Responses:

1. The Series A Convertible Preference Shares converted into Ordinary Shares on a 1-to-1 basis and had no expiration date.

2. The Series B Convertible Preference Shares converted into Ordinary Shares on a 1-to-1 basis and had no expiration date.

3. The Series C Convertible Preference Shares converted into Ordinary Shares on a 1-to-1 basis and had no expiration date.

4. Such shares are held by Pacven Walden Ventures V, L.P. and affiliated funds. Mr. Tan disclaims beneficial ownership of these shares except to the extent of any pecuniary interest therein.

	Michael Morehead, by Power of Attorney	10/15/2012
	** 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 4 (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).
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