The Federal Reserve Bank of New York will ask its primary dealers, as part of best practices, to raise their upfront cash collateral for MBS trades. A NY Fed spokesman denied that the change in collateral requirements was a reaction to the recent collapse of MF Global, a primary dealer. Since its last foray into the agency MBS business in 2010, the agency has been considering raising the margin for MBS deals, he said. The spokesman said a best practices guidance issued by the NY Fed’s Treasury Market Practices Group in September 2010 requires trading desks to consider...