Exhibit (6)(b)

ASSIGNMENT OF INVESTMENT MANAGEMENT AGREEMENT

WHEREAS, an assignment of the Investment Management Agreement (the “Investment Management Agreement”), dated as of December 12, 2006, between Kayne Anderson MLP Investment Company (the “Company”) and Kayne Anderson Capital Advisors, L.P., from Kayne Anderson Capital Advisors, L.P., as assignor, to KA Fund Advisors, LLC, as assignee, does not constitute an assignment within the meaning of the Investment Company Act of 1940, as amended (the “Act”), because it does not result from a change of actual control or management of the investment advisor to the Company and therefore, pursuant to Rule 2a-6 of the Act, does not constitute an assignment for purposes of Section 15(a)(4) of the Act.

WHEREAS, the Board of Directors, including those directors who are not “interested persons” within the meaning of the Act, has unanimously approved this assignment.

NOW THEREFORE, Kayne Anderson Capital Advisors, L.P. hereby assigns to KA Fund Advisors, LLC, as of the date below, all rights, benefits and obligations arising to it under the Investment Management Agreement.

IN WITNESS WHEREOF, the undersigned has executed this assignment, by a person duly authorized, effective as of the 31st day of December, 2006.

KAYNE ANDERSON CAPITAL ADVISORS, L.P.

/s/ David J. Shladovsky

Name: David J. Shladovsky

Title: Managing Director

ACCEPTANCE OF ASSIGNMENT

KA Fund Advisors, LLC hereby accepts the foregoing assignment and agrees to be bound by all of the terms and conditions of the Investment Management Agreement.

IN WITNESS WHEREOF, the undersigned has executed this acceptance, by a person duly authorized, effective as of the 31st day of December, 2006.

KA FUND ADVISORS, LLC

By: Kayne Anderson Capital Advisors, L.P., its managing member

/s/ Kevin S. McCarthy

Name: Kevin S. McCarthy

Title: Managing Director