Standard & Poor’s cut to junk the ratings on certain securities, backed by U.S. mortgage bonds, that it granted AAA grades when they were created last year by Credit Suisse Group, Jefferies Group Inc. and Royal Bank of Scotland Group Plc. The reductions were among downgrades to 308 classes of so- called re-remics, or re-securitizations, created from 2005 through 2009, the New York-based ratings company said today in a statement. About $150 million of the debt issued last year, as recently as July, with top rankings were lowered below investment grades, according to data compiled by Bloomberg.