The counterparty was the troubled bond insurer ACA Financial Guaranty, which Moody's cut dramatically from A to triple-C one day in December.

FORBES: You Should Worry About Ambac

That "hands across Wall Street" effort seems unlikely now, though banks are meeting with individual bond insurers, including Ambac and Financial Guaranty (FGIC), two of the companies that are the targets of the Buffett offer.

FORBES: Buffett To The Rescue!

One motion, filed by Mr. Tourre, centers on the question of whether the SEC can include as evidence a recorded phone call from January 2007 between a Goldman saleswoman and an executive at ACA Financial Guaranty Corp.

WSJ: From 'Fabulous Fab' to Grad Student

"Prospective opportunities in the municipal sector may be narrower than in the past, given changing perceptions about municipal risk among buyers, lower confidence in the financial guaranty industry broadly and a trend toward alternative forms of execution, " including uninsured bonds, Moody's said Wednesday.

FORBES: Magazine Article

Most Mexican companies don't sell it, but Houston-based Stewart Title Guaranty and Fidelity National Financial (parent to Chicago and Fidelity Title) do.

FORBES: A Casa of Your Own

Assured Guaranty, and the other big monolines like MBIA and Ambac Financial Group, use credit default swaps and other credit derivatives to insure bonds.

FORBES: Left Overs of the Financial Crisis: Last Monoline to Lose AAA-Rating