Share prices closed sharply lower, with the benchmark Nikkei index shedding more than 330 points, its biggest decline in nearly six months, after a fall in US stocks overnight triggered massive selling, dealers said. The Nikkei 225 Stock Average ended the day down 330.38 points or 2.4 pct at 13,359.51. It was the biggest drop for the Nikkei since April 18, when it fell by 432.25 points to 10,938.44. The broader-based TOPIX index of all First Section issues fell 38.30 points or 2.7 pct to 1,371.37, also the largest fall in nearly six months. Losers overwhelmed gainers 1,508 to 123, with 34 issues unchanged. Volume reached 2.8 bln shares, down from 2.9 bln shares yesterday. "A fall in US stocks gave investors [reason] to sell, as many felt the Japanese market was overheating in recent days," said Ryuta Otsuka, a strategist at Toyo Securities. "Japanese share prices have been kept at high levels as expectations [on the economy] came first, [but] not necessarily reflecting the reality," said Otsuka. But he said the release of corporate earnings for the fiscal first half to September, due in about two weeks, should provide evidence on whether expectations that the economy is on the mend due to robust domestic demand has basis. In the chip sector, Hitachi plunged 37 yen or 4.9 pct to 720, Fujitsu dipped 40 yen or 4.9 pct to 771, Oki Electric Industry tumbled 21 yen or 5.1 pct to 388 and Mitsubishi Electric closed down 44 yen or 5.9 pct to 700. Among precision machinery makers, Canon dropped 290 yen or 4.6 pct to 6,030, Hoya lost 210 yen or 5.1 pct to 3,930 and Ricoh fell 65 yen or 3.45 pct to 1.819. Oil refiners and distributors of oil products also lost ground as Showa Shell Sekiyu KK retreated 99 yen or 6.5 pct to 1,425, Nippon Oil closed down 42 yen or 4.3 pct to 935 and Cosmo Oil shed 24 yen or 4.2 pct to 553.