HANOI (Reuters) - A Vietnamese court is set to make a key ruling in the country’s biggest-ever fraud case, in a trial that has spotlighted Vietnam’s ability to tackle financial crime at a time when foreign banks are heeding government calls to invest.

The Ho Chi Minh City People's High Court is scheduled to rule on Wednesday on whether to uphold a judgment that the central perpetrator of a 4.9 trillion dong ($215 million) theft is responsible for returning some of the stolen money, rather than the individual's employer at the time, state-controlled VietinBank CTG.HM.

The ruling comes as financial firms such as investment banks and global buyout funds flock to Vietnam, hoping to capitalize on a period of privatization and capital-raising deals in the fast-growing emerging Southeast Asian economy.

The chief executive of one victim, depositor Saigonbank Berjaya Securities JSC (SBBS) - a unit of Malaysia's Berjaya Corporation Bhd BGRO.KL - told Reuters that if the ruling was upheld, she had little hope of recouping her bank's $10 million from the perpetrator, who was sentenced to life imprisonment.

“We can’t afford to lose the case. This represents 70 percent of our capital. Our business may get suspended,” Josephine Yei said in an interview.

VietinBank, formally Vietnam Joint Stock Commercial Bank for Industry and Trade, and majority owner State Bank of Vietnam - the country’s central bank - did not respond to emailed requests for comment.

In many economies, banks can be liable for embezzlement of depositors’ funds if negligence of the bank is established. In Vietnam, interpretation of liability law becomes more open when the perpetrator goes beyond their responsibility, a lawyer said.

“Different understandings lead to different decisions,” said Nguyen Thanh Ha, chairman of Hanoi-based SBLAW. “Vietnam doesn’t have case laws for such cases so it depends completely on the mind of the jury.”

Court documents showed indebted Huynh Thi Huyen Nhu and 22 accomplices were convicted in 2014 for “misappropriation of funds” from 15 victims in 2010 and 2011.

Nhu used her title as a senior VietinBank manager to encourage customers to deposit funds at a particular branch. She and accomplices used fake official documents to appropriate the funds, according to the indictment.

SBBS’ Yei said her company had 210 billion dong deposited at VietinBank at the end of August 2011, and was shocked when two months later just 1 percent of the money remained. She said she has spent the intervening years trying to recover the funds and that SBBS and four other victims brought the latest appeal.

The appeal covers only 1 trillion dong of the broader case.

“It’s judgment day for us,” said Yei, whose firm employs 55 people and has 94 investors, 93 of whom are Vietnamese.

VietinBank is Vietnam's second-largest listed bank by market value. It is 64.46 percent state-owned, with its next-biggest shareholder Japan's MUFG Bank Ltd [MTFGTU.UL], a unit of Mitsubishi UFJ Financial Group Inc 8306.T, with 19.7 percent.

“This case should be handled under international practices, otherwise it could have a bad effect on Vietnam’s investment and business environment and then investors will lose trust,” economist and former government advisor Le Dang Doanh told Reuters by phone. “We have to avoid that. We have to create trust.”

(The story has been refiled to correct name of re-branded MUFG unit in the penultimate paragraph.)