New regulatory requirements including a controversial plan to assign ratings on a rotating basis are encouraging firms to test the traditional approaches to rating MBS and ABS, but some observers say the reliance on an issuer-pay business model will be tough to change. New rating services are coming up with new ways to assess risk with more dynamic, ongoing reviews and more sources of information, and theyre less reliant on being fed information, said Stephen Kudenholdt, co-chair of the capital markets practice at SNR Denton. But the expectation that the market would shift to an investor-paid model clearly hasnt...