SEOUL, June 21 South Korea's main KOSPI share index was down 1.96 1,814.20 points as of 0058 GMT.
Stocks on the move on Friday include:
**POSCO LOWEST SINCE 2009**
Shares in steelmaker POSCO, backed by U.S. billionaire investor Warren Buffett, slumped more than 3 percent to their lowest levels since the 2009 global economic downturn, rattled by Chinese data pointing to slower economic growth in the world's top steel consumer.
China's factory activity weakened to a nine-month low in June as demand faltered, a preliminary survey showed on Thursday, heightening the risk of a sharper second quarter slowdown.
China is the bellwether for the Asian steel market as it is the world's top consumer and producer of steel.
Stocks in POSCO, which ranks third in market value in South Korea after Samsung Electronics and Hyundai Motor , fell as much as 3.1 percent to 300,000 Korean won ($260) per share, their lowest level since March 3, 2009.
Steelmakers led the broader market's losses, with the steel subindex tumbling 3.6 percent to their lowest levels in about three years. ($1 = 1145.7000 Korean won) (Reporting by Hyunjoo Jin; Editing by Anupama Dwivedi)