Some 50 bankers were on trial Monday in Vietnam's capital of Hanoi for alleged graft and mismanagement causing $69 million in losses.
The case is part of communist authorities' efforts to tackle corruption.
Among those accused were Ocean Bank's former chairman Ha Van Tham and general manager Nguyen Xuan Son, who were accused of embezzling $2.2 million and abuse of power in appropriating another $8.8 million. They were also accused of economic mismanagement.
Being convicted of embezzlement carries the possibility of a death sentence.
At the time the bank was 20 percent owned by state oil-and-gas giant PetroVietnam, where Son had previously served as chairman.
Another 44 senior Ocean Bank executives were accused of abuse of power or economic mismanagement. Five executives from different companies were also named in the case.
Several female defendants wept when asked by the judge to confirm identities of their parents and children.
The case was first brought to trial in February, but judges asked police to investigate further and prosecutors pressed for embezzlement charges to be added against the bank's two former leaders.
In May 2015, the State Bank of Vietnam took over Ocean Bank after the bank reported losses of $445 million and bad debts accounting for nearly 50 percent of its total outstanding loans.
The trial is expected to last more than three weeks.
Vietnam ranks 113 out of 176 countries in the International Transparency's 2016 corruption index.
The Communist Party and government have stepped up their anti-corruption drive in recent years with courts sentencing several senior executives to death.