Talking to Russian journalists in Minsk on October 11, Belarusian President Alyaksandr Lukashenka said Baumgertner had been shocked to hear the news.
He said the charges were changed based on new evidence that had emerged.
He also said Belarus was ready to extradite Baumgertner to Russia if Moscow wants to investigate the case, saying Baumgertner caused "more damage to Russia than to Belarus."
Baumgertner, a Russian citizen, was arrested in Minsk in August.
He was the chairman of the Belarusian Potash Company (BKK), a now-defunct joint venture between Uralkali and a Belarusian potash firm, Belaruskali.
His announcement in July that Uralkali was leaving BKK led to a steep drop in the commodity's price, affecting the Belarusian economy.