The government has deployed thousands of troops and assigned guards to Supreme Court judges while embassies have issued travel warnings due to fears of a violent backlash if the tycoon's funds are seized on Friday.
Thaksin's supporters, known as Red Shirts for their signature garb, have vowed to demonstrate after the verdict, expecting that he will lose at least some of the assets frozen after he was deposed in a 2006 coup. They have insisted any action will be non-violent.
"We will wait and see what the court says, but any injustice will bring about a phenomenon," Red Shirt leader Jatuporn Prompan told AFP, adding that the government "underestimates the Red Shirts".
The current Thaksin-hating administration has done little to quell fears of trouble, analysts say, instead stoking anxieties by casting the Red Shirts as a dangerous force in a bid to take the focus off the fragile governing coalition.
At least 20,000 extra security personnel have been deployed across Bangkok and pro-Thaksin regions, including around the homes of judges, politicians and government and commercial institutions.
Last week a bomb was defused near the Supreme Court and a grenade exploded at government offices, prompting the United States, Britain and Australia to warn people visiting Bangkok to exercise caution.
The government has announced it will cede control of security to the army and even declare an emergency if necessary, but says it hopes to control the situation.
"We hope that the security measures that we have put in place can handle the instability or incidents that can cause violence," government spokesman Panitan Wattanayagorn told AFP.
"If the security measures are employed accordingly we should not have any trouble."
Thailand has been beset by political turbulence since the 2006 coup.
Thaksin's "Yellow Shirt" opponents -- a disparate collection of royalist and military elites -- forced the closure of Bangkok's airports in late 2008 after months of sometimes violent rallies.
Now the Red Shirts, mainly from the rural north and northeast, want to see the return of Thaksin, who is living abroad to avoid a two-year jail term for corruption.
They have numbered no more than 30,000 at protests this year but 100,000 turned out last April, when they forced a major Asian summit to shut down and rioting broke out in Bangkok.
The threat they pose could, however, have been overblown for political gain, said Michael Montesano, an expert on Thai politics at the Institute of Southeast Asian Studies in Singapore.
"The fact that they need to put in place these measures today is a reminder of how little progress the Abhisit government has made since coming to power in changing the political landscape," he said. "I think a lot of it's propaganda."
Eton and Oxford-educated Prime Minister Abhisit Vejjajiva is seen as an elitist among the Red Shirts, who remain a key electoral force.
Talk of an imminent coup is relentless in Thailand, where there have been 18 coups and attempted coups in the 64-year reign of King Bhumibol Adulyadej.
But analysts say Abhisit, who came to power in 2008, will hang on as long as he maintains the wavering support of the country's top brass.
Keep up with the latest business news from the region with the Emirates Business 24|7 daily newsletter. To subscribe to the newsletter, please click here.