AMENDMENT NUMBER SEVEN to the Amended and Restated Letter Agreement

Exhibit 10.23

AMENDMENT NUMBER SEVEN

to the

Amended and Restated Letter Agreement

dated as of October 1, 2004

by and among

NEW CENTURY MORTGAGE CORPORATION

NC CAPITAL CORPORATION

NEW CENTURY CREDIT CORPORATION

and

CITIGROUP GLOBAL MARKETS REALTY CORP.

This AMENDMENT NUMBER SEVEN (this “Amendment Number Seven”) is made this 28th day of September, 2005, among NEW CENTURY MORTGAGE CORPORATION, having an address at 18400 Von Karman, Suite 1000, Irvine, California 92612 (“NC Mortgage”), NC CAPITAL CORPORATION, having an address at 18400 Von Karman, Suite 1000, Irvine, California 92612 (“NC Capital”), NEW CENTURY CREDIT CORPORATION, having an address at 18400 Von Karman, Suite 1000, Irvine, California 92612 (“NC Credit”) and CITIGROUP GLOBAL MARKETS REALTY CORP., having an address at 390 Greenwich Street, New York, New York 10013 (“Citigroup”) to the Amended and Restated Letter Agreement, dated as of October 1, 2004, among NC Mortgage, NC Capital, NC Credit and Citigroup, as amended (the “Letter Agreement”).

RECITALS

WHEREAS, NC Mortgage, NC Capital and NC Credit have requested that Citigroup agree to extend the termination date as more expressly set forth below and Citigroup has agreed to such request.

WHEREAS, as of the date of this Amendment Number Seven, each of NC Mortgage, NC Capital and NC Credit represents to Citigroup that it is in compliance with all of the representations and warranties and all of the affirmative and negative covenants set forth in the Letter Agreement and the Amended and Restated Purchase and Sale Agreement, dated as of October 1, 2004, among NC Capital, NC Credit and Citigroup (the “Purchase and Sale Agreement”) and is not in default under the Letter Agreement or the Purchase and Sale Agreement.

NOW THEREFORE, for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, and of the mutual covenants herein contained, the parties hereto hereby agree as follows:

SECTION 1. Effective as of September 28, 2005, the first paragraph of Section 1(a) of the Letter Agreement is hereby amended by deleting the words “September 30, 2005” on the second and third lines thereof and replacing each with “December 29, 2005”.

SECTION 2. Effective as of September 28, 2005, the first paragraph of Section 4(c) of the Letter Agreement is hereby amended by deleting the words “September 30, 2005” on the second and third lines thereof and replacing each with “December 29, 2005”.

SECTION 3. Fees and Expenses. NC Capital agrees to pay to Citigroup all fees and out of pocket expenses incurred by Citigroup in connection with this Amendment Number Seven (including all reasonable fees and out of pocket costs and expenses of Citigroup’s legal counsel incurred in connection