KOSPI falls, foreigners net sellers Korean won weakens against U.S. dollar South Korea benchmark bond yield falls SEOUL, Jan 21 (Reuters) - Round-up of South Korean financial markets: ** South Korean shares retreated on Friday and were set for their biggest weekly fall in 16, weighed down by rekindled fears of heated inflation and aggressive policy tightening by the U.S. Federal Reserve. Both the Korean won and the benchmark bond yield fell. ** By 0214 GMT, the benchmark KOSPI (.KS11) fell 19.89 points, or 0.69%, to 2,842.79, heading for a sixth session of decline in seven. ** It was set for a weekly decline of 2.76%, the sharpest since the week ended Oct. 1. ** Among heavyweights, Samsung Electronics (005930.KS) and SK Hynix (000660.KS) fell 1.31% and 3.60%, respectively, while LG Chem (051910.KS) slid 0.72%. ** Concern that the Fed will aggressively move to raise rates this year is taking a toll on the market, with investors anxiously awaiting the U.S. central bank"s policy meeting next week. ** Volatility in KOSPI has risen in recent weeks ahead of LG Energy Solution"s initial public offering, with institutional and retail investors placing bids valued at record $12.8 trillion and $95.6 billion, respectively. read more ** Meanwhile, customs data showed South Korea"s exports during Jan. 1-20 soared 22% from a year earlier, but that did little to lift the market. ** Foreigners were net sellers of 229.7 billion won ($192.66 million) worth of shares on the main board. ** The won was quoted at 1,193.3 per dollar on the onshore settlement platform , 0.08% lower than its previous close. ** In offshore trading, the won was quoted at 1,192.9, while in non-deliverable forward trading its one-month contract was quoted at 1,193.2. ** In money and debt markets, March futures on three-year treasury bonds rose 0.17 point to 108.29. ** The benchmark 10-year yield fell by 4.8 basis points to 2.509%. ($1 = 1,192.2600 won)