Credit-default swaps market leaders will meet this week in NewYork and London to discuss changes to the contracts in what may bethe biggest revisions since 2009, according to people familiar withthe situation.

Possible changes to standard contracts, which are governed bythe International Swaps and Derivatives Association, include howdebt-for-equity exchanges would be treated after a bankruptcy,specifying that credit swaps only cover losses from defaults thatoccur after their purchase, and clarifying how the date of aso-called credit event is determined, said the people, who askednot to be named because the discussions are private.

ISDA's credit steering committee is considering the changesafter Greece's debt restructuring posed the biggest test for the$26.5 trillion credit swaps market since banks including JPMorganChase & Co. created it more than a decade ago. ISDA, based inNew York, last overhauled the derivatives three years ago in theso-called Big Bang and Small Bang protocols that created a new setof standards to increase transparency and confidence in themarket.