S.Korean stocks trim early gains on profit booking

* KOSPI ends flat, foreigners net buyers

* Korean won strengthens versus U.S. dollar

* South Korea benchmark bond yield rises

* For the midday report, please click

SEOUL, Dec 19 (Reuters) - Round-up of South Korean financial markets: ** South Korean shares trimmed some of their early gains on Thursday, after hitting over seven-month highs, as investors booked profits. Both the Korean won and the benchmark bond yield rose.

** The Seoul stock market’s main KOSPI closed up 1.80 points, or 0.08%, at 2,196.56. The index climbed as much as 0.5% to its highest level since May 3 in early trade, driven by a chipmakers’ rally.

** Investors booked profits as the benchmark index approached 2,200, as they saw the level was difficult to retain without strong earnings, said Ryoo Yong-seok, an analyst at KB Securities.

** Donald Trump on Wednesday became the third U.S. president to be impeached as the House of Representatives formally charged him with abuse of power and obstruction of Congress in a historic step that will inflame partisan tensions across a deeply divided America.

** However as the possibility of Trump’s impeachment is seen to be low, market reaction to the vote remained muted, Ryoo said.

** Foreigners were net buyers of 257.8 billion won ($218.60 million) worth of shares on the main board.

** The won was quoted at 1,165.6 per dollar on the onshore settlement platform, 0.27% higher than its previous close at 1,168.8.

** In offshore trading, the won was quoted at 1,165.3 per U.S. dollar, up 0.1% from the previous day, while in non-deliverable forward trading its one-month contract was quoted at 1,164.0 per dollar.

** MSCI’s broadest index of Asia-Pacific shares outside Japan was down 0.38%, after U.S. stocks were mixed overnight. Japanese stocks fell 0.29%.

** The KOSPI has risen 7.62% so far this year, and gained 2.4% in the previous 30 trading sessions.

** The trading volume during the session in the KOSPI index was 630.99 million shares and, of the total traded issues of 907, the number of advancing shares was 423.

** The won has lost 4.3% against the dollar so far this year.

** In money and debt markets, March futures on three-year treasury bonds fell 0.06 points to 110.43, while the 3-month Certificate of Deposit rate was quoted at 1.53% in late afternoon trade.

** The most liquid 3-year Korean treasury bond yield rose by 2.7 basis points to 1.382% in late afternoon trade, while the benchmark 10-year yield rose by 4.8 basis points to 1.655%. ($1 = 1,179.3300 won) (Reporting by Hayoung Choi; Editing by Rashmi Aich)