* KOSPI falls, foreigners net sellers

* Korean won weakens against dollar

* South Korea benchmark bond yield rises

SEOUL, Sept 18 (Reuters) - Round-up of South Korean financial markets:

** South Korean shares started the week lower on Monday, as chipmakers dropped on concerns about weak demand. The won weakened slightly, while the benchmark bond yield rose.

** The benchmark KOSPI fell 18.60 points, or 0.72%, to 2,582.68 by 0135 GMT.

** Chipmaker Samsung Electronics fell 1.94% and peer SK Hynix lost 1.63%, tracking the Philadelphia Semiconductor Index's 3% drop in the last session.

** The world's top contract chipmaker TSMC has told its major suppliers to delay the delivery of high-end chipmaking equipment, as it grows increasingly nervous about customer demand, Reuters reported on Friday.

** "There are also worries about high oil prices and bond yields, while the main focus this week is on the U.S. Federal Reserve's policy meeting," said Na Jeong-hwan, an analyst at NH Investment Securities.

** Among other index heavyweights, automakers fell, but biopharmaceutical manufacturers rose, while battery makers and online platform companies were mixed.

** Of the total 934 traded issues, 321 shares advanced, while 538 declined.

** Foreigners were net sellers of shares worth 177.9 billion won ($134 million) on the main board so far on Monday.

** The won was quoted at 1,327.1 per dollar on the onshore settlement platform, 0.09% lower than its previous close at 1,325.9.

** In money and debt markets, September futures on three-year treasury bonds fell 0.09 point to 103.06.

** The most liquid three-year Korean treasury bond yield rose by 3.4 basis points to 3.884%, while the benchmark 10-year yield rose by 4.9 basis points to 3.977%. ($1 = 1,327.2900 won) (Reporting by Jihoon Lee and Youn Ah Moon; Editing by Varun H K)