KOSPI rises, foreigners net buyers Korean won weakens against U.S. dollar South Korea benchmark bond yield rises SEOUL, Dec 21 (Reuters) - Round-up of South Korean financial markets: ** South Korean shares rebounded on Tuesday, boosted by chip heavyweights on optimistic sector-wide outlook and as upbeat trade data suggested a sustained economic recovery. The Korean won weakened, while the benchmark bond yield rose. ** By 0210 GMT, the benchmark KOSPI (.KS11) rose 14.56 points, or 0.49%, to 2,977.56, rebounding from a sharp 1.81% decline on Monday. ** Chip giants Samsung Electronics (005930.KS) and SK Hynix (000660.KS) jumped 1.30% and 3.32%, respectively, after Micron Technology Inc (MU.O) delivered stronger-than-expected quarterly results and forecast second-quarter sales and profits will also beat estimates with chip shortages easing in 2022. read more ** Exports for the first 20 days of the month surged 20% from the same period a year earlier, customs agency data showed, with sales of semiconductors and petroleum products surging 27.5% and 88.8%, respectively. ** Gains, however, were capped due to cautious trading amid the global spread of the Omicron coronavirus variant and related curbs. British prime minister said he would tighten virus curbs if needed, after the Netherlands began a fourth lockdown and as other European nations consider Christmas restrictions. read more ** Foreigners turned net buyers, purchasing net 8.3 billion won ($6.97 million) worth of KOSPI shares. ** The won was quoted at 1,192.1 per dollar on the onshore settlement platform , 0.11% lower than its previous close. ** In offshore trading, the won was quoted at 1,191.5 per dollar, down 0.2% from the previous day, while in non-deliverable forward trading its one-month contract was quoted at 1,191.2. ** In money and debt markets, December futures on three-year treasury bonds fell 0.03 point to 109.42. ** The most liquid 3-year Korean treasury bond yield fell by 0.1 basis points to 1.740%, while the benchmark 10-year yield rose by 1.7 basis points to 2.125%. ($1 = 1,191.0000 won) Reporting by Joori Roh; Editing by Vinay Dwivedi