* Trading subdued on China, Europe woes
* SK Innovation, S-Oil shares sag on oil price fall
* KOGAS jumps on news of shale gas exploration
* Foreign investors unload following Vanguard's switch to FTSE index
SEOUL, Oct 4 (Reuters) - South Korean shares dipped on Thursday as concerns about the weak global economy dampened investor confidence.
The Korea Composite Stock Price Index (KOSPI) ticked down 0.2 percent at 1992.68 points, failing to close above the 2,000 mark for the sixth trading session.
"Despite some encouraging U.S. data, global growth prospects remain dim. Uncertainty about Spain continues to weigh down investor sentiment," said Kim Byung-yeon, an analyst at Woori Investment & Securities.
Worries about China are also intensifying after its official purchasing managers' index (PMI) for services on Wednesday confirmed a slowdown had spread to the service sector.
Despite U.S. auto sales data showing an increase in overseas car sales, shares of Hyundai Motor Co failed to rally, closing 0.8 percent lower.
Market heavyweight Samsung Electronics eased 0.2 percent as investors await the release of third-quarter results expected on Friday.
Leading South Korean refiners SK Innovation and S-Oil , fell 2.4 percent and 1.4 percent, respectively, on weaker oil prices.
Shares in Woongjin Coway , a water purifier manufacturer, soared 14.1 percent on news that a local court will hold a hearing on the fate of its troubled parent company on Friday.
State-owned Korea Gas Corp (KOGAS) jumped 6 percent as a budget proposed on Tuesday earmarked 250 billion Korean won ($224.69 million) to develop the shale gas industry.
Foreign investors offloaded 92 billion won worth of shares, in a trend that is expected to continue over the next few months following U.S. fund manager Vanguard group's switch from the MSCI index to the FTSE to track emerging markets.
FTSE, unlike MSCI, classifies South Korea as a developed market.
The KOSPI 200 benchmark of core stocks closed down 0.2 percent, while the junior KOSDAQ inched 0.7 percent higher. Move on day -0.17 percent 12-month high 2,057.28 14 March 2012 12-month low 1,666.52 5 Oct 2011 Change on yr +9.14 percent All-time high 2,231.47 27 April 2011
All-time low 93.10 6 January 1981 ($1 = 1112.6500 Korean won)
(Reporting By Somang Yang; Editing by Kim Coghill)
Keywords: MARKETS KOREA STOCKS/