Bergmann, who is 42 and has a one-year-old child, promised not to hinder investigations into the bankruptcy of ERA Bank, which collapsed in 1999 owing millions of kroons.
He was taken into custody on Dec. 13 last year for fabricating documents during the investigation, and was told he would stay in prison until the end of the preliminary investigation on March 3, 2002.
"The size of the bail is extremely small compared to the 190 million kroon loss he caused by his transactions," said Kaire Hanilene, prosecutor at the Tartu prosecutor's office.
"It is a ridiculously small bail sum."
Bergmann could be charged with fraud, plunder, money laundering, abuse of his professional position and forgery in connection with his management of ERA Bank and its subsidiaries Polaris Elu (Polaris Life) and Polaris Vara (Polaris Assets), said Indrek Raudjalg, spokesman for the state police department.
Money laundering, the most serious of these crimes, carries a 10-year prison sentence.
Bergmann, who is of Estonian and German origin, was met at the prison gates by his parents, who are retired and live in Germany.
"The bail sum is not a huge amount for the middle-class citizens of Germany. German pensioners earn more than the prime minister of Estonia," said his lawyer, Tarmo Pilv.
Arguing that he should be kept in custody, the prosecutor referred to promises Bergmann had made earlier not to interfere with the investigation, promises they said he had later broken.
Bergmann was first arrested in March 2000, when the police tried to hold him and his associates throughout a six-month investigation into possible large scale embezzlement.
On that occasion a court rejected the police application and he was released.
Besides Bergmann, seven others are under investigation for fraud, most of them former employees of ERA Bank.
Bergmann's lawyer protested his client's innocence.
"Unfortunately people of the second and third rank get to court in Estonia. The rest do not," he said.
"If Bergmann is guilty, then those who are blaming him, including some government institutions, are guilty too. ERA Bank did not disappear because of its economic situation. A certain group of people did not want this bank."
In the wake of the Russian crisis the state decided in 1998 to save Forekspank, a competitor, from collapse and let EVEA Bank, which was one-third owned by ERA, go bankrupt.
Clients panicked and withdrew their money.
Only after the court process is over will the size of the final claim against Bergmann become evident, said Pilv.
"Even the prosecutor does not know the total sum of the claims - the preliminary charge was over 200 million kroons, but this fell to 100 million kroons right after a judicial assessment was made."
Bergmann is the second Estonian banker to be imprisoned after Malle Eenmaa, the former head of Maapank, who was sentenced to 18 months in prison for corruption.
Maapank went into bankrupt in 1998 as a result of huge losses incurred on the stock market.