* KOSPI rises, foreigners net sellers
* Korean won weakens versus U.S. dollar
* South Korea benchmark bond yield falls
Seoul, Sept 23 (Retuers) - Round-up of South Korean financial markets: South Korean shares flitted between positive and negative territory on Monday as investors sought clarity on the two-day Sino-U.S. trade negotiation, while local data signalled a weak economy for the world's sixth-largest exporting nation. The Korean won and the benchmark bond yield fell.
** As of 0126 GMT, the Seoul stock market's main KOSPI was up 0.65 points, or 0.03%, at 2,092.17.
** According to Customs Agency, South Korea's Sept. 1-20 average exports per working day dropped 10.3% year-on-year. The country imports more oil relative to the size of its economy than any other Group of 20 nation, according to the World Bank, to power its massive manufacturing sector, a major driver of jobs and trade.
** Already beset by cratering company earnings, as the global economy slows, an escalating trade dispute with Japan and crumbling consumer spending at home, Korea's currency and stock market are among the world's worst performing.
** Elsewhere, U.S. and Chinese deputy negotiators held "productive" talks in Washington this week aimed at improving their trade relationship, the U.S. Trade Representative's office said on Friday without offering further details.
** However, Chinese agriculture officials who were due to visit U.S. farm states next week have cancelled their trip to Montana as the officials will return to China sooner than originally scheduled, the Montana Farm Bureau told Reuters on Friday.
** Foreigners were net sellers of 18.6 billion won ($15.61 million) worth of shares on the main board.
** The won was quoted at 1,192.0 per dollar on the onshore settlement platform , 0.34% lower than its previous close at 1,188.0. ** In offshore trading, the won was quoted at 1,191.7 per U.S. dollar, up 0.1% from the previous session, while in non-deliverable forward trading its one-month contract was quoted at 1,190.2 per dollar.
** MSCI's broadest index of Asia-Pacific shares outside Japan was down 0.04%, after U.S. stocks dropped.
** The KOSPI up 2.48% so far this year, and gained 9.1% in the previous 30 trading sessions.
** The trading volume during the session in the KOSPI index was 145.84 million shares and, of the total traded issues of 890, the number of advancing shares was 356.
** The won lost 6.4% against the U.S dollar so far this year.
** In money and debt markets, December futures on three-year treasury bonds rose 0.02 points to 110.73, while the 3-month Certificate of Deposit rate was quoted at 1.55%.
** The most liquid 3-year Korean treasury bond yield fell by 1.2 basis points to 1.321%, while the benchmark 10-year yield fell by 0.6 basis points to 1.449%.
($1 = 1,191.6800 won) (Reporting by Yuna Park, Editing by Sherry Jacob-Phillips)