* NCsoft tumbles on concerns about game addiction law
* Offshore investors turn net sellers to weigh on market
SEOUL, Jan 17 (Reuters) - Seoul shares traded lower early on Friday as downbeat U.S. corporate results chilled risk sentiment before the full-scale domestic market earnings season starts next week, and offshore investors repositioned as sellers.
The Korea Composite Stock Price Index (KOSPI) was down 0.6 percent at 1,946.28 points as of 0311 GMT.
"Market sentiment was already subdued ahead of the domestic corporate results, but could get worse if big firms disappoint the market as they did on Wall Street overnight," said Oh Seung-hoon, an analyst at Daishin Securities.
On Thursday, Goldman Sachs Group Inc and Citigroup Inc reported that lower bond trading revenue took a bite out of their quarterly profits. Goldman's earnings fell 21 percent. Citigroup's profit missed expectations.
Big names such as Hotel Shilla Co Ltd, Hyundai Motor Co and Samsung Electronics Co Ltd are due to report next week.
Daishin Securities' Oh, however, was confident of strong support at the KOSPI's 1,930 point level where the price-to-book ratio (PBR) nears 1, a level that has prompted bargain hunting in the past.
Steelmaker Dongkuk Steel Mill Co Ltd advanced 2.6 percent after signing a technological cooperation agreement with Japan's JFE Steel Corp on Thursday.
Among declining stocks, online game developer NCsoft Corp plunged 4.4 percent on the possibility of a game addiction bill being passed by lawmakers in February, which would hurt its earnings by limiting gaming hours for non-adult users and impose a 1 percent of fee payment to a game addiction treatment fund.
Automakers Hyundai Motor Co and Kia Motors Corp fell 1.3 percent and 1.9 percent, respectively.
Offshore investors positioned as net sellers near mid-session, selling a net 48.2 billion won ($45.3 million) worth of KOSPI shares to weigh on the index.
Decliners outnumbered advancers 506 to 263.
The KOSPI 200 benchmark of core stocks was down 0.7 percent, while the junior KOSDAQ edged 0.4 percent lower. ($1 = 1063.3500 Korean won) (Reporting by Jungmin Jang; Editing by Eric Meijer)