Bloomberg reports that Standard & Poor’s will give monoline bond insurers a second review, just one month after completing a prior investigation of the insurers’ capital adequacy amid rising losses in U.S. housing. The new assessment comes on the heels of S&P’s decision to update its assumption regarding RMBS performance — HW first reported on the changes Tuesday. From Bloomberg’s coverage:

The ratings company will examine whether insurers including MBIA Inc. and Ambac Financial Group Inc. have enough capital to withstand reductions in the ratings of the mortgage-backed securities they guarantee. The credit test will be completed within a week, said Mimi Barker, a spokeswoman in New York. S&P is now assuming losses on 2006 subprime mortgages will reach 19 percent, up from 14 percent, as housing prices decline further than previously thought. That may make S&P more likely to downgrade the companies along with the mortgage-backed securities they guarantee …

I’m pretty sure this will open up the “rating agencies have no credibility left” debate all over again. I’m also pretty sure that this will mean that at least some guarantors are going to need more capital than they might have previously been told. See an earlier post from Monday for some discussion of this issue.