FT.com – How much is enough? MBIA (NYSE:MBI), the bond insurer caught up in the US subprime mess, on Wednesday detailed its plan to bolster capital – the price of retaining its key credit rating. In a normal world, it should do the trick – providing MBIA with a capital cushion of $3.4bn-$4.5bn according to Bank of America (NYSE:BAC), more than enough to cover the losses Standard & Poor’s modelled as part of its stress test.