Warner Music Group Corp., the world's third-largest record company, rose 4.1 percent in New York trading after Merrill Lynch & Co. upgraded its rating on the stock, recommending that investors buy rather than sell it. "The sell-off has been overdone,'' Jessica Reif Cohen, an analyst at Merrill Lynch in New York, said in a note to investors today. ``Strong sales from Josh Groban's `Noel' and an improving release slate suggest more upside potential than downside risk.'' Warner Music jumped 32 cents to $5.12 at 4:01 a.m. in New York Stock Exchange composite trading. The stock had plunged 79 percent in the 12 months before today. Warner Music's U.S. album market share increased to 20 percent last year from 18 percent in 2006, according to Nielsen SoundScan. Bloomberg)