* KOSPI rises, foreigners net buyers

* Korean won strengthens against U.S. dollar

* South Korea benchmark bond yield rises

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

** South Korean rose for a third straight session on Wednesday as investor optimism about progress in U.S. stimulus talks outweighed preliminary trade data that showed exports out of Asia's fourth-largest economy fell again.

** The won strengthened and the benchmark bond yield rose.

** By 0255 GMT, the benchmark KOSPI rose 7.55 points, or 0.32%, to 2,365.96.

** South Korean exports returned to contraction in the first 20 days of October after growing in September, government data showed on Wednesday.

** A rally is building up on U.S. stimulus hopes once again as more investors are weighing the chances of striking a deal near the U.S. election, Shinhan Investment and Securities' analyst Choi Yoo-jin said.

** Shares of SK Hynix declined 1.2% after its announcement on Tuesday to buy Intel Corp's NAND memory chip business sparked valuation concerns.

** The White House and Democrats in the U.S. Congress moved closer to agreement on a new coronavirus relief package as President Donald Trump said he was willing to accept a large aid bill.

** Foreigners were net buyers of 29.8 billion won worth of shares on the main board.

** The won was quoted at 1,133.7 per dollar on the onshore settlement platform, 0.50% higher than its previous close at 1,139.4.

** MSCI's broadest index of Asia-Pacific shares outside Japan was up 0.25%,.

** The KOSPI has risen 7.66% so far this year, but lost 0.3% in the previous 30 trading sessions.

** The most liquid 3-year Korean treasury bond yield rose by 1.3 basis points to 0.925%, while the benchmark 10-year yield rose by 3.8 basis points to 1.499%. (Reporting by Cynthia Kim and Jihoon Lee; editing by Uttaresh.V)