Share prices closed weaker, with the benchmark Nikkei 225 index falling below the key 16,000 mark, as investors opted to pocket profits amid cautious trading ahead of the first congressional testimony of new US Federal Reserve chairman Ben Bernanke later today, dealers said. The Nikkei 225 Stock Average index ended down 252.04 points or 1.6 pct at 15,932.83, its session low. The broader TOPIX index of all First-Section shares lost 10.96 points or 0.7 pct to 1,624.28, off a low of 1,621.80. Decliners led gainers 979 to 607, with 83 issues unchanged. Volume dropped to 1.89 bln shares from 2.41 bln shares yesterday. Shares got off to a firmer start on the back of overnight gains in New York as a pullback in oil prices and robust retail sales data helped ease concerns about a US economic slowdown. However, once the round of purchases waned, investors eventually chose to take profits before they gauge the new Fed chief's thoughts on the outlook for interest rates. "Market participants turned bearish as caution ahead of Bernanke's speech eventually prevailed in the market. The market was short of upward momentum owing to a dearth of strong fund inflows from overseas investors," said Nikko Cordial Corp equity chief Hiroichi Nishi, noting that foreign investors have been net sellers in pre-opening orders for the sixth trading day in a row. Tokai Tokyo Research Center senior strategist Masayoshi Yano said sentiment was also dampened by large-lot sale orders that surfaced in early afternoon trading. Nishi of Nikko Cordial said retail investors who had earlier bought shares via margin trading decided to liquidate some of their long positions. Among notable losers included high-tech companies, shipbuilders, trading firms, retailers, drug makers and Internet companies. General trading houses retreated, led by Sumitomo Corp which lost 49 yen or 3.2 pct to 1,500, and Itochu tumbled 27 yen or 2.9 pct to 906. In the technology sector, Advantest, the world's largest producer of chip-testing equipment, fell 630 yen or 4.4 pct to 13,620, while Tokyo Electron was down 280 yen or 3.3 pct at 8,220. Internet concern Softbank gave up 160 yen or 4.2 pct at 3,640, and its affiliate Yahoo Japan declined 9,000 yen or 6.4 pct to 132,000 Among winners were Sanyo Electric Co which extended gains, climbing another 4 yen or 1.4 pct to 287, after yesterday announcing a deal with Nokia Corp to set up a joint venture in the US to make third-generation mobile phones.