Moody's Investors Service cut the long-term ratings on the senior debt of four US bank holding companies on Friday, upon completing its review of eight large US banking groups and coupling this with its assumptions about government support in times of stress.  The ratings on the senior debt of Morgan Stanley, Goldman Sachs, JP Morgan and Bank of New York Mellon were lowered by one notch, to Baa2, Baa1, A3 and Aa2, respectively.Moody's said the Federal Deposit Insurance Corp's Single Point of Entry bank resolution framework, introduced under the Dodd-Frank Act, influences risks for bond-holders at the bank holding-company level by reducing the likelihood and predictability of systemic support. SPE is designed to allow regulators to restore the solvency of a distressed entity without using public funds.As envisioned by US regulators, the Single Point of Entry approach would impose losses on US bank holding-company creditors to recapitalise and preserve the operations of the group's systemically important subsidiaries in a stress scenario. As a result, the holding company creditors would be unlikely to receive government support, so signalling a higher risk of default.