South Korean stocks closed lower Thursday as institutional investors unloaded tech shares and the central bank froze its key interest rate as expected, analysts said. The South Korean won fell against the U.S. dollar.

The benchmark Korea Composite Stock Price Index fell 0.15 percent, or 3.02 points, to 2,011.65. The trading volume was moderate at 246.89 million shares worth 4.15 trillion won ($4.1 billion) with gainers leading losers 487 to 330.

The market started lower and maintained the bearish tone in morning trading. In afternoon trading, the market extended its earlier losses to end slightly lower.

“Institutional selling led the fall in the market, with foreign investors reducing their stock purchases,” said Kim Ji-hyung, an analyst at Hanyang Securities Co.

“The central bank’s decision to leave the key interest rate intact had little impact on the market as it had been widely expected,” he said.

The Bank of Korea froze the key interest rate at 2.5 percent for the 13th consecutive month on Thursday.

The market also did not react to quadruple witching day, which refers to the simultaneous expiration of contracts for stock index futures, stock index options, stock options and single stock futures, which usually makes share prices volatile, Kim said.

Market leader Samsung Electronics was the main catalyst for the bearish market, falling 0.63 percent to 1,413,000 won, with its smaller rival LG Electronics dropping 0.64 percent to 77,700 won.

However, chipmaker SK hynix rose 0.85 percent to 47,400 won on hopes of a rise in demand for dynamic random access memory in the second half.

Top auto parts maker Hyundai Mobis and Samsung Fire & Marine Insurance, a non-life insurance unit of Samsung Group, ended in negative territory, falling 1.21 percent to 285,500 won and 2.13 percent to 46,000 won, respectively.

The South Korean won ended at 1,017.70 won to the U.S. dollar, down 2.00 won from Wednesday’s close, as importers bought the greenback. (Yonhap)