* Samsung Elec down 1.3 pct despite record earnings
* Mass futures order could add volatility before options expiry
By Joyce Lee
SEOUL, Jan 8 South Korean shares fell on Tuesday as what appeared to be an unprecedented technical glitch and caution before corporate earnings results suppressed investor appetite - even as Samsung Electronics issued a record profit estimate.
The Korea Composite Stock Price Index (KOSPI) closed down 0.66 percent at 1,997.94 points, losing ground for the fourth session to shave off nearly all of last week's relief-rally gains.
"The index is declining steadily after recent rapid gains. Investors also refrained from making aggressive bets as the fallout from the mistaken KOSPI 200 futures order remains unclear before options expiry date (on Thursday)," said Lim Soo-gyun, an analyst at Samsung Securities.
What appeared to be a technical glitch resulted in a 30 percent increase in KOSPI 200 futures orders on Monday compared to the previous session.
Local newspaper Chosun Ilbo and other media reported an unprecedented 15.6 trillion won worth of mistaken buy orders were made on behalf of an unidentified Hong Kong investor on Monday, of which 2.6 trillion won worth remain unsold and could cause increased volatility in the index.
Blue chip stocks were mostly down. Samsung, which accounted for 17.4 percent of the index as of Tuesday, fell 1.3 percent despite announcing an estimated fourth-quarter operating profit of $8.3 billion on strong smartphone sales and increasing demand for its flat screens for mobile devices.
But shares in CJ Korea Express, South Korea's largest logistics firm, rose 5.1 percent after it announced it will merge with affiliate logistics firm CJ GLS on April 1.
STX Pan Ocean also rose 3.3 percent after the shipper announced it bought a new a bulk vessel, to be called the STX Horizon.
STX Pan Ocean's share price has jumped more than 60 percent in four weeks since largest shareholder STX Corp and affiliates put a roughly 35 percent stake of the shipper on the market.
Local institutional investors sold a net 118.9 billion Korean won ($111.75 million) worth of KOSPI shares, weighing on the main board.
Decliners outnumbered gainers 430 to 370. The KOSPI 200 benchmark of core stocks closed down 0.8 percent, while the junior KOSDAQ edged 0.1 percent higher.
Move on day -0.66 percent
12-month high 2,057.28 14 March 2012
12-month low 1,769.31 25 July 2012
Change on yr -1.6 percent
All-time high 2,231.47 27 April 2011
All-time low 93.10 6 January 1981 ($1 = 1064.0000 Korean won) (Additional reporting by Seongwon Chang and Somang Yang; Editing by Eric Meijer)