As investors worried that the Fed may begin to reduce its bond buying program, the Valley 50 index fell incrementally along with the broader market during the two-week period ended Aug. 14. The Valley 50’s biggest gainer was BNK Petroleum Inc., up 79 percent after it reported good drilling results in its second-quarter filing. Also, zipper manufacturer Talon International Inc. rose nearly 35 percent after it reported a strong quarter. The biggest loser was Capstone Turbine Corp., which announced a 15 percent drop in revenue for the second quarter. Its stock declined 23 percent.