S.Korea stocks end flat ahead of key U.S. data

* KOSPI falls, foreigners net buyers

* Korean won weakens against U.S. dollar

* South Korea benchmark bond yield rises

* For the midday report, please click

SEOUL, Nov 16 (Reuters) - Round-up of South Korean financial markets:

** South Korean shares ended flat on Tuesday, as optimism over U.S.-China talks was partially offset by investor caution ahead of U.S. retail sales data that could give signs of any impact inflation has had on consumer spending.

** The won weakened, while the benchmark bond yield rose.

** The benchmark KOSPI closed flat at 2,997.21, erasing early gains of 0.41%. The index ended 1.04% higher at 2,999.52 on Monday.

** Among the heavyweights, technology giant Samsung Electronics fell 0.14%, while peer SK Hynix added 0.90%. Platform companies Naver and Kakao slid 1.34% and 1.16%, respectively.

** Investor focus was on U.S. retail sales data due later in the day that will provide another hint about the health of the world’s biggest economy. It is expected to have risen 1.1% last month, according to a Reuters poll.

** U.S. President Joe Biden and his Chinese counterpart Xi Jinping held a three-hour virtual talk, with the two leaders stressing their responsibility to the world to avoid conflict, while the official Xinhua news agency described the meeting as “frank, constructive, substantive and fruitful”.

** Foreigners were net buyers of 241.3 billion won ($204.50 million) worth of shares on the main board.

** The won ended at 1,179.9 per dollar on the onshore settlement platform, 0.13% lower than its previous close.

** In offshore trading, the won was quoted at 1,179.5 per dollar, up 0.3% from the previous day, while in non-deliverable forward trading its one-month contract was quoted at 1,180.8.

** In money and debt markets, December futures on three-year treasury bonds fell 0.13 point to 108.53.

** The most liquid 3-year Korean treasury bond yield rose by 4.5 basis points to 1.957%, while the benchmark 10-year yield climbed 3.0 basis points to 2.329%.

$1 = 1,179.9500 won Reporting by Joori Roh; Editing by Sherry Jacob-Phillips