BANGKOK--Thailand’s Constitutional Court will on Friday rule whether to dissolve an upstart opposition political party that has challenged the military establishment, over accusations it benefited from an illicit loan from its wealthy founder.

The newly formed Future Forward Party came a surprise third in a general election last March, winning the support of many young people and 81 of the 500 seats contested in parliament.

The party, led by charismatic auto-parts billionaire Thanathorn Juangroongruangkit, has emerged as a major adversary to the government of Prime Minister Prayuth Chan-ocha, a former military leader who overthrew an elected government in a 2014 coup.

This will be the second time in weeks that the Constitutional Court will decide the fate of a party that has won over many young voters disillusioned by years of strife and what many of them see as political stagnation.

Last month, the Constitutional Court rejected accusations the party sought to overthrow the monarchy, an allegation that could have seen it banned.

On Friday, the party again faces a ban over an Election Commission accusation it took a 191.2 million baht ($6.08 million or 676 million yen) loan from Thanathorn.

The law limits donations from an individual to 10 million baht.

The party and Thanathorn, 41, deny wrongdoing. Thanathorn said the financial arrangements between himself and the party were aboveboard.

“If we could turn back time ... we would do the same thing because it was transparent and verifiable,” he said in a Facebook post this week.

In another post he wondered about the possibility of a fair hearing.

“Why do we face a party dissolution, a ban on executives and even jail for wanting to build a new type of honest political party with good intentions and transparency?”

Thanathorn was suspended from parliament in November for breaching election law after he was accused of holding shares in a media company when he registered as a candidate. He said he sold the shares before registering.

If Future Forward were to be banned, most of its legislators could keep their seats in parliament but top leaders could be banned from politics, strengthening the slim parliamentary majority of Prayuth’s coalition.

Future Forward and its allies argue that the rules for last year’s election were written to ensure a victory for Prayuth’s pro-army party.

Prayuth says a Constitution drawn up under the auspices of the military during its rule, and which enshrines a political role for the military, is necessary to ensure stability after years of political chaos and occasional violence.