Redwood Trust is getting ready to issue its first jumbo MBS of 2012 backed by a more diverse pool of prime mortgages than the company’s previous transaction. Fitch Ratings said it plans to give AAAsf ratings to the senior bonds in Sequoia Mortgage Trust 2012-1, which will enjoy 8.25 percent credit enhancement from subordinate classes. That’s a stiffer credit enhancement level than on Redwood’s two jumbo deals from last year, which had 7.40 percent and 7.50 percent support levels at issuance. Two factors appeared to play the biggest part in the higher credit support levels: more diverse collateral and more...