Ruling comes weeks after brother Thaksin Shinawatra was freed from hospital detention on parole.

The ruling on Monday is the latest legal success for the influential Shinawatra family. In February, Yingluck’s brother Thaksin – a two-time prime minister and figurehead of the Pheu Thai Party – was released on parole after serving six months into a commuted prison sentence for abuse of power and conflicts of interest.

Yingluck and five others were accused of mishandling 240 billion baht ($6.7bn) and not running a proper bidding process for a  2013 campaign set to promote Yingluck’s government’s infrastructure projects.

All nine judges in Thailand’s Supreme Court acquitted all defendants, saying in a statement they found “no intention” to benefit two major media outlets that won the contract at the time.

“The project was done according to the regulations,” the court statement added.

Yingluck, who has lived abroad since 2017 to avoid jail over a subsidy scheme that caused billions of dollars in state losses, was not present at the court but was represented by her lawyer.

Thailand’s anticorruption commission, which had filed the original complaint, has 30 days to appeal.

One of the defendants, Niwatthamrong Boonsongpaisan, who served as a deputy prime minister, told reporters they all “received the mercy from the court to dismiss the case”.

Yingluck, 56, served as Thailand’s first female prime minister from 2011 until 2014 when her government was toppled in a coup.

In 2017, Thailand’s Supreme Court sentenced Yingluck in absentia to five years in jail over a separate case of negligence in a rice subsidy promise to farmers during the 2011 election.

Thaksin had spent 15 years abroad after fleeing in the wake of his 2006 overthrow but made a dramatic return in August to face justice. He was transferred to hospital on his first night in jail and soon after, his eight-year term was commuted to one year by the king.

His return and early release have fuelled persistent rumours that the tycoon made a behind-the-scenes deal with his powerful enemies, claims his allies and rivals have denied.

The clearance to Yingluck in the last remaining case against her could add to media speculation that she too will seek to return to Thailand.

Prime Minister Srettha Thavisin, a close ally of the Shinawatras, has said the issue has not been raised.

Coverage of Thaksin’s release has been dominated by expectations he will seek to exert influence on Srettha’s government, or through his daughter Paetongtarn, who is Pheu Thai Party leader and eligible to become prime minister.

Srettha has repeatedly been asked by media if he would remain in charge with Thaksin now freed, questions he has rebuffed, insisting that he is still calling the shots in government. Thaksin has insisted he is retired and has been suffering from various health problems.