* Samsung Elec falls 1.3 pct on foreign selling
* Techs underperform on iPhone 5 demand worry
* SK Hynix bucks tech trend, up 1 pct
* CJ Corp drops 4.1 pct on profit-taking
By Somang Yang
SEOUL, Jan 16 South Korean shares closed at their lowest level since Dec. 12 on Wednesday as jitters about weakening smartphone demand hurt heavyweight Samsung Electronics and most technology stocks.
The Korea Composite Stock Price Index (KOSPI) fell 0.3 percent to close at 1,977.45 points.
Industry leader Samsung Electronics was flat around mid-day, but lost ground after the South Korean won weakened. The stock, which shed 2.6 percent on Tuesday, fell 1.3 percent for the day.
When the won weakened, "foreigners dumped Samsung Electronics shares, which deepened market losses," said Kim Ho-yoon, an analyst at Hana Daetoo Securities.
The won was quoted at 1,059 to the dollar at 0615 on Wednesday, compared with Tuesday's domestic close at 1,056.5.
Most tech stocks extended losses from Tuesday, when they were rattled by a report in Japan's Nikkei business daily that Apple Inc cut orders for LCD panels by half as demand for its iPhone 5 was weaker than expected.
LG Display, one of the panel suppliers named in the report, fell 1.6 percent on Wednesday after losing 3.5 percent the day before.
However, chipmaker SK Hynix Inc bucked the trend, rising 1 percent as contract prices of computer memory chips jumped 10 percent in the first half of January amid tight supply and accelerating demand from PC makers.
Builders outperformed with the sector sub-index up 2 percent. Daelim Industrial, which has been talking with Vietnam's Petrolimex about building a refinery there, rose 5.2 percent.
CJ Corp the holding company of the CJ conglomerate, fell 4.1 percent on profit-taking. The share-price had risen nearly 75 percent in the last six months.
Overall, declining shares outnumbered winners 468 to 346.
Foreign investors sold a net 92 billion won ($87.08 million) worth of KOSPI shares, weighing on the main board.
The KOSPI 200 benchmark of core stocks closed down 0.4 percent, while the junior KOSDAQ edged 0.1 percent lower.
Move on day -0.32 percent
12-month high 2,057.28 14 March 2012
12-month low 1,769.31 25 July 2012
Change on yr -2.64 percent
All-time high 2,231.47 27 April 2011
All-time low 93.10 6 January 1981 ($1 = 1056.50 Korean won) (Editing by Richard Borsuk)