* KOSPI ends at 3-week high

* Foreigners' net buying of KOSPI shares largest since March 11

* Korean won strengthens against U.S. dollar

* South Korea benchmark bond yield falls

* For the midday report, please click

SEOUL, Aug 4 (Reuters) - Round-up of South Korean financial markets:

** South Korean shares ended at a near three-week high on Wednesday, driven by strong foreign inflows into chip heavyweights, offsetting worries about rising cases of corovirus' Delta variant. The won gained, while the benchmark bond yield fell.

** The KOSPI ended up 43.24 points, or 1.34%, at 3,280.38, its highest closing since July 15 and extending gains to a third straight session.

** Foreigners bought net 914.2 billion won ($799.58 million) worth of shares on the main KOSPI board, the largest daily amount since March 11.

** On Tuesday, they purchased net 689.6 billion won worth of shares in chip giants Samsung Electronics and SK Hynix, Korea Exchange data showed.

** Samsung Electronics jumped 1.84%, while peer SK Hynix added 0.83%. Internet giant Naver and messenger app operator Kakao also soared 1.17% and 3.82%, respectively.

** South Korea posted a sharp increase in its coronavirus cases on Wednesday, nearing the record daily infections marked last week, as it struggled to tame its fourth wave of coronavirus.

** Most of the Bank of Korea's seven board members said policy tightening is needed to put a brake on the country's red-hot property market, minutes of a July 15 board meeting showed, raising the odds of a rate hike.

** The won ended at 1,143.6 per dollar on the onshore settlement platform, 0.41% higher than last close at 1,148.3.

** In offshore trading, the won was quoted at 1,143.5 per dollar, up 0.4% from the previous day, while in non-deliverable forward trading its one-month contract was quoted at 1,143.8.

** In money and debt markets, September futures on three-year treasury bonds rose 0.10 points to 110.29.

** The most liquid 3-year Korean treasury bond yield fell by 2.4 basis points to 1.418%, while the benchmark 10-year yield fell by 2.2 basis points to 1.868%. ($1 = 1,143.3500 won) (Reporting by Joori Roh; Editing by Rashmi Aich)