Exhibit 99.12

BARCLAYS	200 Park Avenue
CAPITAL	New York NY 10166
	USA
	Tel +1 (212) 412 4000

(Telecopy to Tesia Sommer of JPMorgan at 212-270-1063 )

Acceptance of Request for Extension

Tuesday, December 19, 2006

Aetna Inc.
151 Farmington Avenue
Hartford, CT 06156

Re: Amended and Restated Five-Year Credit Agreement dated as of January 20, 2006 (the “Credit Agreement”)

Attention: Alfred P. Quirk, Vice President, Finance and Treasurer

Dear Al:

We have received your Extension Request, dated December 5, 2006, and pursuant to Section 2.06(c) (Maturity of Loans) of the above-referenced Credit Agreement, we hereby agree to the extension set forth in such request. Upon the effectiveness of the Extension Request in accordance with Section 2.06(c) of the Credit Agreement, the new Maturity Date will be January 20, 2012.

We have made a notation of this extension on the Schedule of Loans, Payments of Principal attached to our Syndicated Note(s).

Please note that our commitment amount remains unchanged.

Very truly yours,

BARCLAYS BANK PLC

By:	/s/ Nicholas Bell
	Name: Nicholas Bell
	Title: Director