S.Korean stocks notch weekly gain on economic optimism

* KOSPI rises, foreigners net buyers

* Korean won strengthens against U.S. dollar

* South Korea benchmark bond yield rises

* For the midday report, please click

SEOUL, March 26 (Reuters) - Round-up of South Korean financial markets:

** South Korean shares closed higher on Friday, ending the week with a slight gain, as optimism from improving U.S. economic data and an upgrade of growth forecast for the domestic economy lifted sentiment.

** The Korean won strengthened, while the benchmark bond yield rose.

** The benchmark KOSPI ended 32.68 points higher, or 1.09%, at 3,041.01. For the week, the index gained 0.049%.

** Among heavyweights, technology giant Samsung Electronics rose 0.37% and peer SK Hynix gained 1.50%. LG Chem was up 1.78% and Naver added 0.79%.

** The International Monetary Fund upgraded South Korea’s 2021 growth forecast on Friday to 3.6% from 3.1% previously, supported by a rebound in tech exports and added fiscal stimulus.

** In the United States, the number of Americans filing new claims for unemployment benefits dropped to a one-year low last week.

** South Korean shipbuilders surged. Samsung Heavy Industries closed up 6.0% after winning 2.8 trillion won order, while Korea Shipbuilding & Offshore soared 11.4% on 637 billion won order.

** Foreigners were net buyers of 296.6 billion won worth of shares on the main board.

** The won was quoted at 1,129.3 per dollar on the onshore settlement platform, up 0.35%.

** In offshore trading, the won was quoted at 1,129.9 per dollar, up 0.5% from the previous day, while in non-deliverable forward trading its one-month contract was quoted at 1,129.0.

** The trading volume on KOSPI was 1,015.98 million shares. Of the total traded issues of 910, the number of advancing shares was 543.

** The most liquid 3-year Korean treasury bond yield rose by 2.4 basis points to 1.112%, while the benchmark 10-year yield rose by 3.3 basis points to 2.000%.

$1 = 1,133.0300 won Reporting by Cynthia Kim; Additional reporting by Jihoon Lee