U.S. satellite radio company Sirius XM's EBITDA generation and discretionary cash flow have improved, largely as a result of operating synergies and integration-related cost savings. The company plans to issue $550 million of senior notes, which we are rating at 'B-' with a recovery rating of '5'. We are affirming our 'B' corporate credit rating on Sirius XM. The positive rating outlook reflects the company's prospects for continued EBITDA and cash flow growth and declining debt leverage. NEW YORK (Standard&Poor's) March 12, 2010--Standard&Poor's Ratings Services said today it assigned satellite radio company Sirius XM Radio Inc.'s proposed $550 million senior notes due 2015 our issue-level rating of 'B-' (one notch lower than the 'B' corporate credit