SecProbe.io

August 31, 2010
 Mr. Mark S. Casady Chief Executive Officer and Chairman LPL Investment Holdings Inc. One Beacon Street
Boston, MA 02108

Re: LPL Investment Holdings Inc.
Amendment No. 3 to Registrati on Statement on Form S-1
Filed August 10, 2010
  File No. 333-167325

Dear Mr. Casady:

We have reviewed your filing and have the following comments.  In some of our
comments, we may ask you to provide us with  information so we may better understand your
disclosure.
 Please respond to this letter by amending your registration statement and providing the
requested information.  If you do not believe  our comments apply to your facts and
circumstances or do not believe an amendment is appropriate, please tell us why in your
response.
 After reviewing any amendment to your re gistration statement and the information you
provide in response to these comments, we may have additional comments.
 Recent Developments, page 8

 1. In an appropriate section of the prospectus, please describe  the escrow and contingent
payment in greater detail, including a descri ption of the “specified matters” for the
escrow and the maximum amount of the contin gent payment.  Please also include the
acquisition agreement as an exhibit to th e registration statement or tell us why you
believe you are not required to do so.
 Principal and Selling Shareholders, page 124

 2. Please disclose the total number of “Other selling shareholders ” that will be included in
the Form 8-K referenced in f ootnote 14 to the table on page 125.

We urge all persons who are responsible for th e accuracy and adequacy of the disclosure
in the filing to be certain that the filing incl udes the information the Securities Act of 1933 and
all applicable Securities Act rules require.  Since the company and its management are in

Mr. Mark S. Casady Chief Executive Officer and Chairman LPL Investment Holdings Inc. August 31, 2010 Page 2

possession of all facts relating to a company’s disc losure, they are responsible for the accuracy
and adequacy of the disclosures they have made.
Notwithstanding our comments, in the event you request acceleration of  the effective date
of the pending registration statement please pr ovide a written statement from the company
acknowledging that:
• should the Commission or the staff, acting purs uant to delegated authority, declare the
filing effective, it does not foreclose the Co mmission from taking any action with respect
to the filing;

• the action of the Commission or the staff, acting pursuant to delegated authority, in
declaring the filing effective, does not relieve the company from its full responsibility for
the adequacy and accuracy of the disclosure in the filing; and

• the company may not assert staff comments a nd the declaration of effectiveness as a
defense in any proceeding initiated by the Commission or any person under the federal securities laws of the United States.

Please refer to Rules 460 and 461 regarding re quests for acceleration.  We will consider a
written request for acceleration of  the effective date of the regi stration statement as confirmation
of the fact that those reques ting acceleration are aware of thei r respective responsibilities under
the Securities Act of 1933 and the Securities Excha nge Act of 1934 as they relate to the proposed
public offering of the securities specified in th e above registration stat ement.  Please allow
adequate time for us to review any amendment prior to the requested effective date of the
registration statement.
 You may contact Howard Ef ron, Staff Accountant, at (202) 551-3439 or Kevin Woody,
Branch Chief, at (202) 551-3629 if you have que stions regarding comments on the financial
statements and related matters.  Please contac t Kristina Aberg, Attorney-Advisor, at (202) 551-
3404 or me at (202) 551-3655 with any other questions.
Sincerely,

Sonia Gupta Barros Special Counsel
 cc: Julie H. Jones, Esq.  Keith F. Higgins, Esq.  Ropes & Gray LLP