|1||NAMES OF REPORTING PERSONS|
I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
|William Blair & Company, LLC
|2||CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE
|3||SEC USE ONLY|
|4||CITIZENSHIP OR PLACE OF ORGANIZATION|
|222 W. Adams, Chicago, IL 60606|
|NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:||5||SOLE VOTING POWER|
|6||SHARED VOTING POWER|
|7||SOLE DISPOSITIVE POWER|
|8||SHARED DISPOSITIVE POWER|
|9||AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON|
|10||CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)|
|11||PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)|
|12||TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)|
Name of Issuer
COWEN GROUP, INC.
Address of Issuer’s Principal Executive Offices
599 Lexington Avenue, New York, NY 10022, United States
Name of Person Filing
WILLIAM BLAIR & COMPANY, L.L.C.
Address of Principal Business Office or, if none, Residence
222 W. Adams, Chicago, IL 60606
Title of Class of Securities
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:
Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o).
Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c).
Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c).
Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C 80a-8).
An investment adviser in accordance with §240.13d-1(b)(1)(ii)(E);
An employee benefit plan or endowment fund in accordance with §240.13d-1(b)(1)(ii)(F);
A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
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);
A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J).
A 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:
Amount beneficially owned: 5,026,204
Percent of class: 4.43%
Number of shares as to which the person has:
Sole power to vote or to direct the vote: 5,026,204
Shared power to vote or to direct the vote: 0
Sole power to dispose or to direct the disposition of: 5,026,204
Shared power to dispose or to direct the disposition of: 0
Ownership of Five Percent or Less of a Class
Ownership of More than Five Percent on Behalf of Another Person.
Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company
Identification and Classification of Members of the Group
Notice of Dissolution of Group
|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 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.|
Date: February 5, 2013
|/s/ Michelle Seitz|
|Name: Michelle Seitz|
|Title: Principal & Head of Investment Management|
Intentional misstatements or omissions of fact constitute Federal criminal violations (See 18 U.S.C. 1001)