Genta ( GNTA) sank 25% after setting plans to sell 20 million shares in an bid to raise gross proceeds totaling $16 million. The stock was dropping 28 cents to 82 cents early Wednesday. With only 30 minutes gone in the trading session, more than 15 million shares had already traded. The average volume for a full day is about 5.8 million shares. Genta said the closing should take place around Sept. 22. The shares are being sold under the company's registration statement declared effective by the Securities and Exchange Commission in May 2004 and the prospectus supplement dated Tuesday.