Shares of American River Bankshares, the parent company of American River Bank, declined 10 percent, while stock of GenCorp Inc. – the parent of Aerojet -- fell 7 percent after its chief financial officer and controller left the Rancho Cordova company. And Chapeau Inc. — a clean-tech company in El Dorado Hills — plunged 26 percent in trading Monday. But there were a few winners, including FirstGold Corp., a Cameron Park company that will start mining for gold in Nevada in the next few months. FirstGold shares gained 29 percent, as investors looked for a safe haven during the tough economic times. But the big winner? Pacific Ethanol, with a more than 50 percent increase of its stock. The Sacramento-based company announced the opening of its latest ethanol plant in Stockton on Monday.