Shares of Reebok International Ltd., the United States' No. 2 athletic shoe and apparel maker, rose sharply in after-hours trading Tuesday amid media reports that it will be acquired by German sporting goods company Adidas-Salomon AG.

The deal would give adidas about 20 percent of the U.S. market, putting it in a far more strategic position to challenge industry leader Nike Inc.

Reebok shares surged 16 percent to $51 in after-hours trading late Tuesday following several media reports -- which all cited unnamed sources close to the negotiations -- of the deal to buy the Canton, Mass.-based company. Earlier, Reebok shares rose $1.19 Tuesday to close at $43.95 on the New York Stock Exchange.