Stocks scored gains Thursday for the fifth time in six sessions as the bulls showed confidence. The Nasdaq popped 1.3%, while the S&P 500 added 0.8%. The IBD 50 advanced 0.9%. Volume in the stock market rose on the Nasdaq but slipped on the NYSE. The Nasdaq’s recent gains include two gap-up days — a 1.5% gush Monday and a 1.3% surge Thursday. Sizable price gains in rising volume point to institutional buying, also known as accumulation.