The judge in the capital Naypyidaw handed down the verdict within moments of the court convening, said the source, who declined to be identified because the trial is being held behind closed doors, with information restricted.
The case centered on allegations that Suu Kyi, 76, accepted 11.4 kg (402 oz) of gold and cash payments totaling $ 600,000 from her protege-turned-accuser, former Yangon chief minister Phyo Min Thein.
Suu Kyi had denied the charges and called the allegations “absurd.”
It was not immediately clear if Suu Kyi would be transferred to a prison. She has been held in an undisclosed location, where junta leader Min Aung Hlaing said she could remain after earlier guilty verdicts in other cases.
The international community has dismissed the trials as farcical and has demanded her immediate release.
The military says Suu Kyi is on trial because she committed crimes and is being given due process by an independent judiciary. A spokesman for the junta was not immediately available for comment.
Since her arrest on the morning of February 1 coup last year, Suu Kyi has been charged with multiple crimes from violations of electoral and state secrets laws to incitement and corruption, accusations her supporters say are trumped up to kill off any chance of a political comeback.