Round-up of South Korean financial markets:

** South Korean shares ended marginally lower on Tuesday, reversing early gains as investors booked profits amid caution ahead of major corporate earnings and the U.S. Federal Reserve's policy meeting.

** The won strengthened, while the benchmark bond yield fell.

** The benchmark KOSPI closed down 1.84 points, or 0.07%, at 2,498.81, erasing its early gain of as much as 1.12%. The fall came after three straight sessions of gains.

** "The KOSPI erased gains as investors booked profits in a wait-and-see mood ahead of big events this week," said Park Kwang-nam, an analyst at Mirae Asset Securities.

** South Korea's exports likely rose for a fourth straight month in January on growing chip sales, with the headline figure pushed up further by calendar effects, a Reuters poll showed.

** Among index heavyweights, chipmaker Samsung Electronics fell 0.13% but peer SK Hynix gained 1.41%, while battery maker LG Energy Solution slid 0.66%.

** Hyundai Motor shed 2.86% and sister automaker Kia Corp lost 1.90%, while search engine Naver and instant messenger Kakao were down 1.18% and 1.81%, respectively.

** Of the total 937 traded issues, 497 shares advanced, while 386 declined.

** Foreigners were net sellers of shares worth 13.6 billion won ($10.23 million) on the main board, snapping a seven-session streak of buying.

** The won ended onshore trade at 1,329.4 per dollar, 0.47% higher than its previous close at 1,335.7.

** In money and debt markets, March futures on three-year treasury bonds rose 0.13 point to 104.92.

** The most liquid three-year Korean treasury bond yield fell by 3.2 basis points to 3.272%, while the benchmark 10-year yield fell by 8.0 basis points to 3.355%. ($1 = 1,329.7500 won) (Reporting by Jihoon Lee; Editing by Sohini Goswami)