The Federal Trade Commission piled on new antitrust charges against Intel Corp. on Wednesday, seeking to end what it described as a decade of illegal sales tactics that have crippled rivals and kept prices for computer chips artificially high.

U.S. stocks trimmed gains on Wednesday, with the Dow turning negative after the Federal Reserve reiterated its intention to keep interest rates low for the foreseeable future to ensure a sustainable economic recovery.

Shares of Technitrol Inc. tumbled Wednesday after the electronics components maker said it will sell $50 million in convertible senior notes in a private offering.

Shares of Achillion Pharmaceuticals Inc. surged Wednesday after the company said its hepatitis C drug candidate showed positive “proof-of-concept” results, while meeting safety and tolerability goals in an early-stage study.

Shares of Adobe Systems Inc. climbed in midday trading after the company said demand for its software picked up strongly in November.

Shares of Ceragon Networks Ltd. slipped Wednesday after Wedbush Securities cut the company’s rating, saying investors have largely priced in the company’s growth potential.

Shares of chip makers Advanced Micro Devices Inc. and Nvidia Corp. surged Wednesday after the Federal Trade Commission sued Intel Corp. for alleged “anticompetitive tactics.”

Shares of oil exploration company Cobalt International Energy Inc. slipped following their New York Stock Exchange debut on Wednesday.

Shares of industrial equipment maker Roper Industries Inc. rose Wednesday after Standard & Poor’s said it will add the company to the S&P 500 index next week.

Shares of Auxilium Pharmaceuticals Inc. fell Wednesday as investors mulled mixed results from the drug candidate Xiaflex in a midstage study focused on Peyronie’s disease, or penile curvature.