Bangkok - Thai shares lost 6.4 per cent of their value Monday in what was believed to be the steepest fall in Asia as investors pulled money out of regional bourses.

The Stock Exchange of Thailand (SET) index ended at 551.80, down 38.25 points or 6.4 per cent.

"All markets were down today but Thailand's fell hard because there are also concerns about our political situation," said Mongkol Phuengphaetha, an analyst at Adkinsons Securities.

Although the US finally pushed through its 700 billion dollar bail-out on Friday, markets have not responded favourably out of fears that the amount is not enough and more trouble is on the horizon.

"Foreign investors are playing a big role. They don't mind if they make a loss they just want money in hand," said Mongkol.

Besides the global insecurity about equities, Thailand is also suffering mounting political uncertainties.

On Sunday, Chamlong Srimuang, the leader of a protest movement that has occupied Government House since August 26, was arrested by police on charges of treason.

His arrest and detention are expected to heighten political tensions in the capital. (dpa)