BANGKOK, May 27 (Reuters) - Shares in some Thai state-owned companies fell on Tuesday, in contrast to a rise in the main index, amid concerns that top executives could be fired and boardroom policies altered after the government was toppled by the military last week.
Thailand's biggest energy firm, PTT, was among the worst hit as worries grew over possible changes after the military government issued a series of orders transferring senior government officials.
PTT stocks, which suffered their biggest drop in almost three months on Monday with a loss of 2.6 percent, fell as much as 1.35 percent at one stage. PTT finished down 0.7 percent, while the main SET index rose 0.3 percent.
PTT is 51.1 percent owned by the finance ministry. The firm's board chairman is Panpre Mahittananukorn, a former member of Puea Thai, the main party in the ousted government.
Finance Ministry Permanent Secretary Rangsan Sriworasat, who is acting as finance minister under the ruling military council, denied any plan to change PTT's board at this stage.
"PTT is a listed company and a board change will need approval from shareholders. Although the finance ministry is a major shareholder of PTT, it still needs to call a shareholders meeting," he told reporters.
Shares in airport operator Airports of Thailand - which could also suffer from a drop in foreign visitors because of the coup - fell almost 1 percent at one point to their lowest in more than three months after a drop of more than 2 percent on Monday. The stock closed down 0.3 percent.
The company is 70 percent owned by the finance ministry and its board chairman, Sita Divari, is also a former member of Puea Thai.
Some other state-owned stocks recouped early losses. National carrier Thai Airways International rose 0.8 percent after an earlier fall of almost 1 percent, while state-run broadcaster MCOT gained 1 percent.
Investors have been lukewarm about Thai stocks for months compared with regional rivals because of prolonged political unrest, which caused the economy to contract 2.1 percent in the first quarter from the previous three months and sent consumer confidence to its lowest in more than 12 years in April.
Foreign investors have offloaded a net 23.4 billion baht ($718 million) worth of stocks over the five sessions since the imposition of martial law on May 20 followed by the military coup on May 22.
Outflows so far this year total 31 billion baht ($951 million), according to Thomson Reuters data.
That compares with net inflows to other markets in Southeast Asia, including Indonesia's 41.9 trillion rupiah ($3.62 billion) and the Philippines' 63.8 billion peso ($1.46 billion).
$1 = 32.6000 Thai baht Reporting by Viparat Jantraprap; Additional reporting by Wilawan Pongpitak; Editing by Alan Raybould and Jacqueline Wong