The stock closed up 7.875, or nearly 12 percent, to 73.625 in trading today. Adjusted for a recent stock split, Amazon has traded as high as 62.625 and as low as 8.875 during the past 52 weeks.
The run-up comes despite continued losses at Amazon.com and warnings that profits from the online music business could be lower than those for books. Many analysts, however, remain bullish about "e-tailing," the latest buzzword for online commerce, and Amazon.com has been a pioneer.
Some analysts speculate that the recent increase in Amazon's stock price may be the result of a "short squeeze" on the shares by arbitrageurs. In a short squeeze, the price of a stock is driven up as short sellers try to cover their losses. The run-up of Internet stocks has caught many traders by surprise.
Under the deal announced today, Muze's music database will be incorporated into Amazon.com's online music store. Amazon.com also gets access to Muze's book and video content.