The court approved bail applications on the condition that Mr Sondhi and the two former managing directors - Saowalak Thiranujanyong and Yupin Chantana - increase their 10 million baht surety to 12 million baht in assets each.
Judges justified the decision by reasoning that the three defendants had been granted bail after trials in two lower courts and that they did not pose flight risks. They were set to be released at 8pm Monday.
The Appeals Court on Aug 7 upheld 20-year jail sentences for the three, who had been found guilty of falsifying loan documents and fraud.
After hearing the judgment, Sondhi was taken to Bangkok Remand Prison, while Saowalak and Yupin were taken to the Central Women's Correctional Institution.
The fourth defendant - Suradet Mukyangkoon, who was also a former managing director - did not appeal the lower's court decision. He was sentenced 2.5 years in prison.
The group was indicted in October 2000 after being accused of falsifying loan-guarantee documents to secure a 1.08-billion-baht loan by the company from Krung Thai Bank, without seeking approval from the board of directors.
The loan was arranged by The M Group, a private company controlled by Mr Sondhi and an MMG shareholder.