BANGKOK — Thailand’s Supreme Court on Friday confiscated $1.4 billion in frozen assets from the nation’s fugitive former prime minister, Thaksin Shinawatra, after finding him guilty of illegally concealing his ownership of a family company and abusing his power to benefit the companies he owned.

But it softened the blow by allowing him to keep the remainder of what had been $2.3 billion in frozen assets, saying that “to seize all the money would be unfair because some of it was made before Thaksin became prime minister.”

The case resonates in Thailand beyond the assets of one man, part of a long-running and sporadically violent confrontation that has divided the country. It has pitted the nation’s rural and urban poor, who support Mr. Thaksin, against the established ruling class, whose control of the political system he challenged during his six years as prime minister.

“This case is very political,” Mr. Thaksin said during a televised response from an undisclosed location outside the country. “The court was used to get rid of a politician. The ruling will be a joke for the world.”