SC 13G

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

Under the Securities and Exchange Act of 1934

Acme Packet Inc.

(Name of Issuer)

Common Stock

(Title of Class of Securities)

004764106

(CUSIP Number)

July 31, 2011

(Date of Event Which Requires Filing of this Statement)

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

     This Schedule is filed pursuant to Rule 13d-1(b)

The information required in the remainder of this cover page (except any items to which the form provides a cross-reference) 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.

CUSIP No. 004764106 

1	NAME OF REPORTING PERSON Ameriprise Financial, Inc. S.S. or I.R.S. Identification No. of Above Person IRS No. 13-3180631
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
	(a)   o
	(b)   þ*
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION
	Delaware
		5	SOLE VOTING POWER
NUMBER OF			-0-
SHARES		6	SHARED VOTING POWER
BENEFICIALLY
OWNED BY			2,594,047
EACH		7	SOLE DISPOSITIVE POWER
REPORTING
PERSON			-0-
WITH		8	SHARED DISPOSITIVE POWER
			7,932,346
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	7,932,346
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES
	Not Applicable
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
	11.93%
12	TYPE OF REPORTING PERSON
	CO

* This filing describes the reporting person’s relationship with other persons, but the reporting person does not affirm the existence of a group.

CUSIP No. 004764106 

1	NAME OF REPORTING PERSON Columbia Management Investment Advisers, LLC S.S. or I.R.S. Identification No. of Above Person IRS No. 41-1533211
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
	(a)   o
	(b)   þ*
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION
	Minnesota
		5	SOLE VOTING POWER
NUMBER OF			-0-
SHARES		6	SHARED VOTING POWER
BENEFICIALLY
OWNED BY			2,594,047
EACH		7	SOLE DISPOSITIVE POWER
REPORTING
PERSON			-0-
WITH		8	SHARED DISPOSITIVE POWER
			7,932,346
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	7,932,346
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES
	Not Applicable
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
	11.93%
12	TYPE OF REPORTING PERSON
	IA

* This filing describes the reporting person’s relationship with other persons, but the reporting person does not affirm the existence of a group.

CUSIP No. 004764106 

1	NAME OF REPORTING PERSON Columbia Select Large Cap Growth Fund S.S. or I.R.S. Identification No. of Above Person IRS No: 36-3376651
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
	(a)   o
	(b)   þ*
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION
	Massasschutes
		5	SOLE VOTING POWER
NUMBER OF			3,945,630
SHARES		6	SHARED VOTING POWER
BENEFICIALLY
OWNED BY			-0-
EACH		7	SOLE DISPOSITIVE POWER
REPORTING
PERSON			-0-
WITH		8	SHARED DISPOSITIVE POWER
			3,945,630
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	3,945,630
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES
	Not applicable
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
	5.93%
12	TYPE OF REPORTING PERSON
	IV

* This filing describes the reporting person’s relationship with other persons, but the reporting person does not affirm the existence of a group.

1(a) Name of Issuer:	Acme Packet Inc.
1(b) Address of Issuer’s Principal	100 Crosby Drive
Executive Offices:	Bedford, MA 01730
2(a) Name of Person Filing:	(a) Ameriprise Financial, Inc. (“AFI”)
	(b) Columbia Management Investment
	Advisers, LLC (“CMIA”)
	(c) Columbia Select Large Cap Growth
	Fund(“SLCG”)
2(b) Address of Principal Business Office:	(a) Ameriprise Financial, Inc.
	145 Ameriprise Financial Center
	Minneapolis, MN 55474
	(b) 100 Federal St.
	Boston, MA 02110
	(c) 100 Federal St.
	Boston, MA 02110
2(c) Citizenship:	(a) Delaware
	(b) Massachusetts
	(c) Massachusetts
2(d) Title of Class of Securities:	Common Stock
2(e) Cusip Number:	004764106

3 Information if statement is filed pursuant to Rules 13d-1(b) or 13d-2(b):

(a) Ameriprise Financial, Inc.

A parent holding company in accordance with Rule 13d-1(b)(1)(ii)(G). (Note: See Item 7)

(b) Columbia Management Investment Advisers, LLC

An investment adviser in accordance with Rule 13d-1(b)(1)(ii)(E)

(c) Columbia Select Large Cap Growth Fund

An investment company registered under Section 8 of the Investment Company Act of 1940.

4	Incorporated by reference to Items (5)-(9) and (11) of the cover page pertaining to each reporting person.
	CMIA, as an investment adviser to SLCG, may be deemed to beneficially own the shares reported herein by SLCG. Accordingly, the shares reported herein by CMIA include those shares separately reported herein by SLCG.

AFI, as the parent company of CMIA, may be deemed to beneficially own the shares reported herein by CMIA. Accordingly, the shares reported herein by AFI include those shares separately reported herein by CMIA.

Each of AFI and CMIA, and the subsidiaries identified on the attached Exhibit I, disclaims beneficial ownership of any shares reported on this Schedule.

5	Ownership of 5% or Less of a Class: Not Applicable
6	Ownership of more than 5% on Behalf of Another Person:
	The clients of Columbia Management Investment Advisers, LLC, a registered investment adviser, including investment companies registered under the Investment Company Act of 1940 and other managed accounts, have the right to receive or the power to direct the receipt of dividends and proceeds from the sale of shares included on this Schedule. As of July 31, 2011, only SLCG, a registered investment company, owned more than 5% of the class of securities reported herein. Any remaining shares reported herein by CMIA are owned by various other accounts managed by CMIA on a discretionary basis. To the best of CMIA’s knowledge, none of these other accounts own more than 5% of the outstanding shares.
7	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company:

AFI: See Exhibit I

8 Identification and Classification of Members of the Group:

Not Applicable

9 Notice of Dissolution of Group:

Not Applicable

10

Certification:

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

TABLE OF CONTENTS

EX-99.I

EX-99.II

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.

Dated: August 10, 2011
	Ameriprise Financial, Inc.
	By:	/s/ Wade M. Voigt  Name: Wade M. Voigt Title: Director — Fund Administration
	Columbia Management Investment Advisers, LLC
	By:	/s/ Amy Johnson  Name: Amy Johnson
		Title: Chief Operating Officer
	Columbia Funds Series Trust I, on behalf of its series Columbia Select Large Cap Growth Fund
	By:	/s/ Scott R. Plummer  Name: Scott R. Plummer
		Title: Senior Vice President, Secretary and Chief Legal Officer
	Contact Information
	Wade M. Voigt
	Director — Fund Administration
	Telephone: (612) 671-5682

Exhibit Index

Exhibit I	Identification and Classification of the Subsidiary which Acquired the Security Being Reported on by the Parent Holding Company.
Exhibit II	Joint Filing Agreement

EX-99.I

Exhibit I

to

Schedule 13G

Ameriprise Financial, Inc., a Delaware Corporation, is a parent holding company. The classification and identity of the relevant subsidiaries is as follows:

Investment Adviser — Columbia Management Investment Advisers, LLC is an investment adviser registered under section 203 of the Investment Advisers Act of 1940.

EX-99.II

Exhibit II

to

Schedule 13G

Joint Filing Agreement

The undersigned persons agree and consent to the joint filing on their behalf of this Schedule 13G dated August 10, 2011 in connection with their beneficial ownership of Acme Packet Inc. Each of Columbia Select Large Cap Growth Fund and Columbia Management Investment Advisers, LLC authorizes Ameriprise Financial, Inc. to execute the Schedule 13G to which this Exhibit is attached and make any necessary amendments thereto.

Ameriprise Financial, Inc.
By:	/s/ Wade M. Voigt Wade M. Voigt
	Director — Fund Administration
Columbia Management Investment Advisers, LLC
	By: /s/ Amy Johnson Amy Johnson
	Chief Operating Officer
Columbia Funds Series Trust I,
on behalf of its series Columbia Select Large Cap Growth Fund
By:	/s/ Scott R. Plummer Scott R. Plummer
	General Counsel

August 10, 2011

Peter Minihane
Acme Packet Inc.
100 Crosby Drive
Bedford, MA 01730

RE: Schedule 13G

Enclosed pursuant to Rule 13d-1(b) under the Securities Exchange Act of 1934 is a report on Schedule 13G reporting beneficial ownership at July 31, 2011 by Ameriprise Financial, Inc. and its related entities in Common Stock of Acme Packet Inc.

Sincerely,

Wade M. Voigt
Director — Fund Administration

Enclosure