UPDATE 1-Thai police arrest two people in stock rumour probe

(Recasts, adds quotes, details of arrests)

BANGKOK, Nov 1 (Reuters) - Police in Thailand arrested two people on Sunday on suspicion of spreading rumours about the health of the country's 81-year-old king that triggered a slide in stock prices, police said.

The two were charged with "feeding untrue information through a computer system which undermined the security of the nation", said Capt. Suttichai Tienbhodhi of the Crime Suppression Division in Bangkok.

Thai stocks .SETI plunged a combined 7.2 percent on Oct. 14-15 as rumours circulated over the health of King Bhumibol Adulyadej, who has been in hospital for more than a month, before rebounding 3.5 percent the following day.

Teeranun Wipuchanin, a 43-year-old unemployed former stock trader arrested at Bangkok's Suvarnabhumi Airport, said she had translated a news story by U.S.-based financial news and data provider Bloomberg LP.

"What I've done was translating documents from foreign media Bloomberg," she told reporters after her arrest.

"I got it from Internet," she added. "Everybody on that day wanted to know what caused the market to fall. The stock market had already dropped and we did the translation in the evening."

It was not clear for whom she provided the translation.

Police also arrested Kata Pajajariyaponga, 35, an employee of Thai stock broker KT Zmico Securities.

They were charged under the 2007 Computer Offence Act covering the posting of false computerised information that causes harm to national security and the public. They face up to five years in jail and a 100,000 baht ($3,000) fine if convicted.

CONTINUING INVESTIGATION

Strict lese majeste and national security laws in Thailand make comment on royal matters risky.

The king, the world's longest-reigning monarch, is regarded as semi-divine by many of the country's 63 million people.

His health is a sensitive topic in financial markets because he is seen as the sole unifying figure in a politically polarised country with a long history of coups and upheaval.

The king was admitted to hospital on Sept. 19 with a lung infection and fever and has been seen only once in public since then, on Oct. 23, when he visited royal monuments in the hospital grounds. The palace has said he is recovering.

Police said last week they may charge four or five people suspected of spreading rumours about the king's health.

The Securities and Exchange Commission has said it is seeking trading information on two accounts from two foreign brokers, Credit Suisse in Hong Kong (CSGN.VX: Quote, Profile, Research) and UBS in Singapore (UBSN.VX: Quote, Profile, Research), in connection with the market plunge and was also looking at one domestic account. [ID:nBKK116990]

Credit Suisse and UBS have so far not commented on the case.

The Department of Special Investigation, which comes under the Justice Ministry, is also conducting an inquiry into possible stock trading irregularities, which it expects to complete in late November.

Finance Minister Korn Chatikavanij plans to meet with the Securities and Exchange Commission (SEC) and the Stock Exchange of Thailand (SET) on Monday to look at ways of managing volatility on the stock market.

Bloomberg is a competitor of Thomson Reuters (TRI.N: Quote, Profile, Research) (TRI.TO: Quote, Profile, Research).

(Reporting by Viparat Jantraprap; Writing by Jason Szep; Editing by John Chalmers) ($1=33.44 Baht) ((jason.szep@thomsonreuters.com; +66 2 648 9720. Reuters messaging jason.szep.reuters.com@reuters.net))