The illegal online gambling site “No Hu,” which first started in 2018, saw transactions of up to $110m a month.
The $2.6bn bust is the biggest of its kind in Vietnam, where online gambling and private card rooms are banned.
Players bought credit from agents who would then pay out in cash if they won, or give loans to customers on a losing streak against collateral such as motorbikes or other assets.
There are reportedly hundred of No Hu agents across Hanoi and millions of accounts have been created for the game.
Along with the 16 people arrested in raids, a large number of mobile phones and ATM cards were also seized.
The website has been deactivated but the report did not say what had happened to the money it had generated.
Last year saw a number of gambling-related arrests in Vietnam, including the arrest of Khá, a high-profile public figure with nearly two million YouTube subscribers.
He was sentenced to 10 years and six months in prison for organising illegal gambling.
