* Weak yen, foreign selloff pressure exporters
* Automakers down for third session on earnings shock
* Korea Exchange Bank up more than 5 pct on share swap
SEOUL, Jan 28 (Reuters) - Seoul shares ticked lower on Monday morning, extending losses to an 8-week low due to a weakening yen and concerns about fourth-quarter earnings.
The Korea Composite Stock Price Index (KOSPI) fell 0.3 percent to 1,940.33 points as of 0211 GMT, with foreign investors selling a net 2.33 billion won ($2.17 million) worth of shares near mid-session.
"Investors have begun preempting concerns about exporters' outlooks since automakers announced weak earnings last week, while large-caps continue to be pressured by foreign selloffs," said Kim Hyung-ryol, an analyst at Kyobo Securities.
South Korean shares have fallen 4.2 percent year-to-date as of last Friday, underperforming a 2 percent gain by Asian peers' as the weakening yen soured the outlook for local exporters and foreign investors sold down their holdings.
A decision by U.S. fund manager Vanguard to switch from the MSCI index to the FTSE to track markets for its $67 billion emerging market fund is expected to wipe about 9 trillion won ($8.5 billion) from Seoul stocks by July.
Tech heavyweight Samsung Electronics extended losses to fall 2.5 percent near mid-session, touching its lowest price since Nov. 21.
"Concerns about South Korean tech firms' fundamentals has increased, with high-end smartphone device shipments expected to slow down this year," said Park Young-joo, an analyst at Woori Investment & Securities.
Automakers lost ground for a third session, with Hyundai Motor down 0.5 percent while sibling Kia Motors slid 3.2 percent in the aftermath of weaker-than-expected earnings last week.
Among daily movers, Korea Exchange Bank (KEB) rose 5.3 percent after parent company Hana Financial Group Inc announced on Monday it will seek 100 percent of Korea Exchange Bank through a share swap.
The planned swap of 5.28 KEB shares for 1 Hana Financial share will be completed in early April, with KEB to be delisted by April 26.
Declining shares outnumbered winners 406 to 347. The KOSPI 200 benchmark of core stocks was down 0.5 percent, while the junior KOSDAQ edged 0.1 percent lower. ($1 = 1074.3000 Korean won) (Reporting by Joyce Lee; Editing by Richard Pullin)