GABELLI EXPLAINS SALE OF GENCORP <GY> SHARES Mario Gabelli, head of New York investment firm Mario Gabelli and Co, said he sold some shares of GenCorp Inc <GY> as part of a "portfolio rebalancing" process to meet the needs of his more than 600 clients. He said as the stock moved up following acquisition proposals from a group formed by AFG Industries Inc <AFG> and Wagner and Brown, some of his clients were overweighted. Regarding the company's shareholders meeting Tuesday, Gabelli told Reuters, "there was nothing said that caused me to sell or buy." He still thinks "values are 140 dlrs per share or more" and has clients that asked to buy more. Gabelli said he amended certain filings with the Securities and Exchange Commission because his clients are now passive investors. "We wanted to remove our clients from the process unfolding between GenCorp and Wagner and Brown," he said. He said he was pleased that chairman A. William Reynolds stated at the meeting that he found the concept of greenmail to be "repugnant." Greenmail refers to a corporation buying out a shareholder at a premium not available to others.