December 6, 2010 Navigant Consulting, Inc. Chicago, IL 60606

Exhibit 10.21

December 6, 2010

Navigant Consulting, Inc.

00 X. Xxxxxx Xxxxx

Xxxxxxx, XX 00000

Re:   First Amendment to Fourth Amended and Restated Credit Agreement, dated as of May 31, 2007 (as amended, restated, extended, supplemented or otherwise modified in writing from time to time, the “Credit Agreement”), among Navigant Consulting, Inc., a Delaware corporation, the other Borrowers party thereto, the Guarantors party thereto, the Lenders from time to time party thereto and Bank of America, N.A., as Administrative Agent

Ladies and Gentlemen:

Reference is hereby made to the Credit Agreement described above. Capitalized terms used herein without definition shall have the meanings ascribed to such terms in the Credit Agreement. The Loan Parties have advised the Lenders that Events of Default exist as a result of the Loan Parties’ (a) failure to comply with Section 8.02 of the Credit Agreement by maintaining Investments in the Foreign Borrowers in excess of those permitted by such section, (b) failure to promptly notify the Lenders and the Administrative Agent of such failure to comply with Section 8.02 of the Credit Agreement as required by Section 7.03(a) of the Credit Agreement, and (c) incorrect certifications and representations and warranties as to the absence of such Events of Default resulting from the foregoing failures (hereafter referred to collectively as the “Existing Default”).

The parties hereto agree that:

1. The Lenders hereby waive the Existing Default. The waiver described in this Section 1 is a one-time waiver and shall be effective only in the specific circumstances provided for above and only for the purposes for which given.

2. Schedule 8.02 to the Credit Agreement is hereby amended and replaced with Schedule 8.02 attached hereto; and

3. Section 8.02(c) of the Credit Agreement is hereby amended to read as follows:

(c) Investments in any Person that is a Loan Party prior to giving effect to such Investment; provided, however, that the amount of all such Investments made by the Domestic Loan Parties in the Foreign Borrowers shall not exceed $75,000,000 in the aggregate at any time outstanding, exclusive of Investments set forth in Schedule 8.02

This letter agreement is a Loan Document. All references in the Credit Agreement and the other Loan Documents to the “Credit Agreement” shall be deemed to refer to the Credit Agreement as amended hereby.

Except as modified hereby, all of the terms and provisions of the Credit Agreement and the other Loan Documents shall remain in full force and effect.

This letter agreement shall become effective upon (i) the execution hereof by the Loan Parties, the Required Lenders and the Administrative Agent and (ii) the receipt by the Administrative Agent, for the

account of each Lender executing this letter agreement, an amendment fee equal to 0.01% of each such Lender’s Revolving Commitment and outstanding Term Loan.

This letter agreement may be executed in one or more counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument. Delivery of executed counterparts of this letter agreement by telecopy or other secure electronic format (.pdf) shall be effective as an original.

[Remainder of page intentionally blank.]

This letter agreement shall be governed by and construed in accordance with the laws of the State of Illinois.

Sincerely,

BANK OF AMERICA, N.A.,

as Administrative Agent

By:  /s/  Xxx Xxxx

Name:     Xxx Xxxx

Title:  Vice President

ACCEPTED AND AGREED AS OF THE DATE FIRST ABOVE WRITTEN:

COMPANY:		NAVIGANT CONSULTING, INC., a Delaware corporation By: /s/  Xxxxxx X. Xxxxx
		Name: Xxxxxx X. Xxxxx Title: Exec V.P. & CFO
U.K. BORROWER:		NAVIGANT CONSULTING (EUROPE) LIMITED, a corporation organized and existing under the laws of England and Wales By: /s/  Xxxxx X. Xxxxxx
		Name: Xxxxx X. Xxxxxx Title: President and COO
CANADIAN BORROWER:		NAVIGANT CONSULTING LTD., a corporation organized and existing under the laws of the Province of Ontario By: /s/  Xxxxxx X. Xxxx
		Name: Xxxxxx X. Xxxx Title: Vice President

LENDERS:		BANK OF AMERICA, N.A., as a Lender, L/C Issuer and Swing Line Lender By: /s/  Xxxxx X. Xxxxxxx
		Name: Xxxxx X. Xxxxxxx Title: Vice President
		BANK OF AMERICA, N.A., acting through its Canada branch, as Canadian Lender By: /s/  Xxxxxx Sales xx Xxxxxxx
		Name: Xxxxxx Sales xx Xxxxxxx Title: Vice President
		RBS CITIZENS, N.A., as a Lender By: /s/  M. Xxxxx Xxxxx, III
		Name: M. Xxxxx Xxxxx, III Title: Vice President
		SUNTRUST BANK, as a Lender By: /s/  Xxxxxxx Xxxxxxxxxxxxx
		Name: Xxxxxxx Xxxxxxxxxxxxx Title: Director
		U.S. BANK, NATIONAL ASSOCIATION, as a Lender By: /s/  Xxxxx X. XxXxxxx
		Name: Xxxxx X. XxXxxxx Title: Senior Vice President
		FIFTH THIRD BANK CHICAGO, A MICHIGAN BANKING CORPORATION, as a Lender By: /s/  Xxxx X. Xxxxx
		Name: Xxxx X. Xxxxx Title: Vice President

THE GOVERNOR AND COMPANY OF THE BANK OF IRELAND,
as a Lender

By: /s/  Xxxxx Xxxx

Name: Xxxxx Xxxx
Title: Authorised Signatory

By: /s/  Xxxxx Xxxxxxxx

Name: Xxxxx Xxxxxxxx
Title: Authorised Signatory

ASSOCIATED BANK, N.A.,
as a Lender

By: /s/  Xxxx Xxxxxxxxx

Name: Xxxx Xxxxxxxxx
Title: VP

TD BANKNORTH, NA,
as a Lender

By:     

Name:
Title:

THE BANK OF TOKYO-MITSUBISHI UFJ, LTD.
as a Lender

By: /s/  Xxxxxx Xxxxxxxxxxxx

Name: Xxxxxx Xxxxxxxxxxxx
Title: Authorized Signatory

HSBC BANK USA, N.A.,
as a Lender

By: /s/  Xxxx X. Xxxxx

Name: Xxxx X. Xxxxx
Title: Relationship Manager

PNC BANK, NATIONAL ASSOCIATION, SUCCESSOR TO NATIONAL CITY BANK,
as a Lender

By: /s/  Xxx Xxxxxx

Name: Xxx Xxxxxx
Title: Senior Vice President

THE NORTHERN TRUST COMPANY,
as a Lender

By: /s/  Xxxxxxx Xxxxx

Name: Xxxxxxx Xxxxx
Title: Vice President

FIRST BANK,
as a Lender

By: /s/  Xxxxxxx X. Xxxxxx

Name: Xxxxxxx X. Xxxxxx
Title: SVP

XXX XXX COMMERCIAL BANK, LTD.,
as a Lender

By:     

Name:
Title:

BMO CAPITAL MARKETS FINANCING, INC., solely for purposes of Section 11.19

By:     

Name:
Title:

BANK OF MONTREAL, solely for purposes of Section 11.19

By:     

Name:
Title: