* KOSPI falls, foreigners net sellers

* Korean won weakens against dollar

* S.Korea benchmark bond yield little changed

SEOUL, May 21 (Reuters) - Round-up of South Korean financial markets:

** South Korean shares fell on Tuesday, led by lacklustre performances among battery makers, with the broader market focus set on U.S. chipmaker Nvidia's earnings and the Bank of Korea's policy meeting due later this week.

** The benchmark KOSPI was down 13.86 points, or 0.51%, at 2,728.28, as of 0042 GMT.

** Dragging the index lower, battery maker LG Energy Solution slid 1.21%, while peers Samsung SDI and SK Innovation fell 2.83% and 1.02%, respectively, weighed by an overnight loss of more than 1% in U.S. electric-vehicle maker Tesla.

** Battery materials makers LG Chem and POSCO Holdings dropped 2.17% and 1.75%, respectively.

** Most other index heavyweights also declined, including automakers and e-commerce firms, but chipmaker SK Hynix rose 1.32%, tracking overnight gains in the Philadelphia Semiconductor Index.

** The Bank of Korea will keep its key policy rate unchanged for an 11th straight meeting on Thursday and through next quarter, followed by a half-point cut in Q4 after the likely start of policy easing from many global peers, a Reuters poll showed.

** South Korea's exports for the first 20 days of May rose 1.5% from the same period a year earlier, according to data.

** Of the total 928 traded issues, 317 shares advanced, while 527 declined.

** Foreigners were net sellers of shares worth 118.9 billion won ($87.20 million) on the main board.

** The won was quoted at 1,363.2 per dollar on the onshore settlement platform, 0.54% lower than its previous close at 1,355.9.

** In money and debt markets, June futures on three-year treasury bonds fell 0.01 point to 104.42.

** The most liquid three-year Korean treasury bond yield fell 0.2 basis point to 3.414%, while the benchmark 10-year yield climbed 0.3 basis point to 3.502%.

($1 = 1,363.4800 won) (Reporting by Jihoon Lee; Editing by Sherry Jacob-Phillips)