ISS Recommends Stockholders Vote “FOR” LaBranche & Co Inc. and Cowen Group, Inc. Merger

NEW YORK, May 31, 2011 (BUSINESS WIRE) —

LaBranche & Co Inc. (“LaBranche”) (NYSE: LAB) and Cowen Group, Inc.
(“Cowen”) (NASDAQ: COWN) today jointly announced that Institutional
Shareholder Services, Inc. (“ISS”), a leading proxy advisory firm, has
recommended that LaBranche stockholders vote “FOR” the adoption of the
merger agreement between Cowen and LaBranche and that Cowen stockholders
vote “FOR” the issuance of shares of Cowen Class A common stock to
LaBranche stockholders pursuant to the merger at their upcoming
respective special meeting of stockholders scheduled to be held on June
15, 2011.

In its report to LaBranche stockholders dated May 29, 2011, ISS stated:

“A vote FOR the proposal is warranted because the proposed deal with
Cowen Group appears to be the most reasonable alternative available to
LaBranche shareholders, and will allow shareholders to participate in
the potential upside of the combined company.”

In its report to Cowen stockholders dated May 29, 2011, ISS stated:

“A vote FOR the proposal is warranted by the significant strategic
opportunities and operating leverage the company would gain through the
transaction, and the indications that the price being paid is
reasonable, despite the acknowledged risk from taking on the potential
liability of the specialist litigation the target firm has been fighting
since 2004.”

LaBranche will hold its special meeting of stockholders on June 15,
2011, at 9:00 a.m., Eastern Time, at the Down Town Association, 60 Pine
Street, New York, New York 10005. Cowen will hold its special meeting of
stockholders on June 15, 2011, at 3:00 p.m., Eastern Time, in the Park
Avenue Room at The InterContinental The Barclay, 111 East 48th Street,
New York, New York 10017. Stockholders of record as of the May 4, 2011
record date are eligible to vote on the proposals.

LaBranche and Cowen encourage all stockholders to vote their shares
promptly by phone, Internet or by mailing their proxy card. The boards
of directors of LaBranche and Cowen unanimously recommend that
stockholders vote “FOR” the adoption of the merger agreement and “FOR”
the issuance of Cowen Class A common stock in the merger, respectively.

LaBranche stockholders in need of assistance voting their shares can
call LaBranche’s proxy solicitor, Morrow & Co., toll-free at (888)
681-0976. Cowen stockholders in need of assistance voting their shares
can call Cowen’s proxy solicitor, MacKenzie Partners, Inc., toll-free at
(800) 322-2885.

About LaBranche & Co Inc.

The LaBranche & Co Inc. is the parent of LaBranche Structured Holdings,
Inc., whose subsidiaries are market-makers in exchange-traded funds on
various exchanges domestically and internationally.

About Cowen Group, Inc.

Cowen Group, Inc. is a diversified financial services firm and, together
with its consolidated subsidiaries, provides alternative investment
management, investment banking, research, and sales and trading services
through its two business segments: Ramius and its affiliates makes up
the Company’s alternative investment management segment, while Cowen and
Company is its broker-dealer segment. Its alternative investment
management products, solutions and services include hedge funds,
replication products, managed futures funds, fund of funds, real estate,
health care royalty funds and cash management services. Cowen and
Company offers industry focused investment banking for growth-oriented
companies, domain knowledge-driven research and a sales and trading
platform for institutional investors. Founded in 1918, the firm is
headquartered in New York and has offices located in major financial
centers around the world.

Important Information For Investors And Stockholders

This communication does not constitute an offer to sell or the
solicitation of an offer to buy any securities or a solicitation of any
vote or approval. In connection with the proposed transaction involving
LaBranche and Cowen, Cowen has filed with the SEC a registration
statement on Form S-4 that includes a joint proxy statement of Cowen and
LaBranche and that also constitutes a prospectus of Cowen. LaBranche and
Cowen have each mailed the final joint proxy statement/prospectus to its
respective stockholders. Investors and security holders are urged to
read these documents and any other relevant documents filed with the
SEC, as well as any amendments or supplements to those documents,
because they will contain important information about LaBranche, Cowen
and the proposed transaction. Investors and security holders may obtain
these documents (including the joint proxy statement/prospectus and any
other documents filed by LaBranche or Cowen with the SEC) free of charge
at the SEC’s website at www.sec.gov.
In addition, the documents filed with the SEC by LaBranche be obtained
free of charge by directing such request to: Investor Relations,
LaBranche & Co, 33 Whitehall Street, New York, NY 10004 or from
LaBranche’s Investor Relations page on its corporate website at www.labranche.com
and the documents filed with the SEC by Cowen may be obtained free of
charge by directing such request to: Investor Relations, Cowen Group,
Inc., 599 Lexington Avenue, New York, NY 10022 or from Cowen’s Investor
Relations page on its corporate website at www.cowen.com.

The directors, executive officers, and certain other members of
management and employees of each of LaBranche and Cowen may be deemed to
be participants in the solicitation of proxies in favor of the proposed
transactions from the stockholders of LaBranche and from the
stockholders of Cowen, respectively. Information about the executive
officers and directors of LaBranche is set forth in LaBranche’s 2010
Form 10-K/A, which was filed with the SEC on April 29, 2011 and
information about the executive officers and directors of Cowen is set
forth in Cowen’s 2010 Form 10-K/A, which was filed with the SEC on May
2, 2011.

Cautionary Notice Regarding Forward-Looking Statements

This communication may contain forward-looking statements including
statements relating to the market opportunity and future business
prospects of LaBranche and Cowen. Such statements are subject to certain
risks and uncertainties that could cause actual results to differ
materially from those expressed or implied in the forward-looking
statements. Consequently, all forward-looking statements made during
this communication are qualified by those risks, uncertainties and other
factors.

These factors include, but are not limited to, (1) the occurrence of any
event, change or other circumstances that could give rise to the
termination of the Agreement and Plan of Merger among Cowen, LaBranche
and Louisiana Merger Sub, Inc. (the “Merger Agreement”); (2) the outcome
of any legal proceedings that may be instituted against Cowen, LaBranche
or others following announcement of the Merger Agreement and
transactions contemplated therein; (3) the inability to complete the
transactions contemplated by the Merger Agreement due to the failure to
obtain the required stockholder approvals, (4) the inability to obtain
necessary regulatory approvals required to complete the transactions
contemplated by the Merger Agreement; (5) the risk that the proposed
transactions disrupt current plans and operations and the potential
difficulties in employee retention as a result of the announcement and
consummation of such transactions; (6) the ability to recognize the
anticipated benefits of the combination of Cowen and LaBranche,
including potential cost savings; and (7) the possibility that Cowen or
LaBranche may be adversely affected by other economic, business, and/or
competitive factors.

Actual results may differ materially and reported results should not be
considered an indication of future performance. Please reference the SEC
filings of LaBranche and Cowen, which are available on their respective
web sites, for detailed descriptions of factors that could cause actual
results to differ materially from those expressed or implied in such
forward-looking statements.

Additional information concerning these and other risk factors is
contained in the joint proxy statement/prospectus, as well as
LaBranche’s and Cowen’s most recently filed Annual Reports on Form 10-K
and Form 10-K/A, subsequent Quarterly Reports on Form 10-Q, recent
Current Reports on Form 8-K, and other SEC filings, as such filings may
be amended from time to time.

Certain statements in this communication relate to future results that
are forward-looking statements as defined in the Private Securities
Litigation Reform Act of 1995. Except for the ongoing obligations of
LaBranche and Cowen to disclose material information under the federal
securities laws, neither LaBranche nor Cowen undertakes any obligation
to release any revisions to any forward-looking statements, to report
events or to report the occurrence of unanticipated events unless
required by law.

SOURCE: Cowen Group, Inc.

LaBranche & Co Inc.:
Jeffrey A. McCutcheon, 212-820-6220
Senior Vice President & Chief Financial Officer
or
Morrow & Co., LLC
Tom Ball or Fred Marquardt
800-662-5200
or
Cowen Group, Inc.:
Peter Poillon, 646-562-1983
Head of Investor Relations
or
MacKenzie Partners, Inc.
Dan Burch or Larry Dennedy
800-322-2885