* KOSPI index drops, foreigners net buyers
* Korean won weakens versus U.S. dollar
* South Korea benchmark bond yield rises
* For the midday report, please click
SEOUL, June 21 (Reuters) - Round-up of South Korean financial markets: South Korea's KOSPI ended weaker on Friday as investors locked in profits after a series of strong gains, while tepid data weighed on the export-driven economy. The Korean won weakened, while the benchmark bond yield rose.
** The Seoul stock market's main KOSPI closed down 5.67 points or 0.27% at 2,125.64 points. The KOSPI gained 1.44% for the week.
** Some investors took profit after the index rose sharply for a third consecutive session until Thursday, said Lee Young-gon, an analyst at Hana Financial Investment. South Korea's weak export data also added to the concerns over the economy, he added.
** South Korea's exports for the first 20 days of this month shrank 10% from a year ago, weighed by fragile overseas sales of semiconductors - its key export item. During the period, semiconductor exports stumbled 24.3% from a year earlier.
** South Korean President Moon Jae-in sacked both of his top economic policy aides on Friday as Asia's fourth-largest economy cools sharply due to prolonged Sino-U.S. trade friction.
** Shares of Korean Air Lines and its parent Hanjin Kal closed down 2.6% and 15.1%, respectively, after Delta Air Lines' stake buy in the parent of its joint-venture partner. Hanjin Transportation also fell 8.1%. ** Foreigners were net buyers of 12.6 billion won ($10.84 million) worth of shares on the main board, while local institutions were net sellers of 132 billion won worth of shares on the main board.
** The won was quoted at 1,164.0 per dollar on the onshore settlement platform, 0.16% lower than its previous close at 1,162.1. On a weekely basis, the currency strengthened 1.83% versus dollar, posting its biggest weekly percentage gain since mid-July 2017.
** In offshore trading, the won was quoted at 1,163.5 per U.S. dollar, down 0.4% from the previous day, while in non-deliverable forward trading its one-month contract was quoted at 1,162.1 per dollar.
** MSCI's broadest index of Asia-Pacific shares outside Japan slipped 0.30%, after U.S. stocks closed up. Japanese stocks fell 0.95%.
** The KOSPI rose 4.14% so far this year, but lost 1.7% in the previous 30 trading sessions.
** The current price-to-earnings ratio is 12.10, the dividend yield is 1.28% and the market capitalisation is 1,242.04 trillion won.
** The trading volume during the session on the KOSPI index was 679.92 million shares and, of the total traded issues of 893, the number of advancing shares was 287.
** The won lost 4.1% against the U.S dollar so far this year.
** In money and debt markets, September futures on three-year treasury bonds fell 0.05 points to 110.58, while the 3-month Certificate of Deposit rate was quoted at 1.80%.
** The most liquid 3-year Korean treasury bond yield rose by 1.5 basis points to 1.435%, while the benchmark 10-year yield rose by 2.4 basis points to 1.567%. ($1 = 1,162.5200 won) (Reporting by Hayoung Choi, Editing by Sherry Jacob-Phillips)