The Russian banker was convicted of large-scale fraud at St. Petersburg Vyborgsky District Court on March 11.
Antonov was arrested in April 2018 for stealing 2.2m euros from the Sovetsky bank along with several other bank executives.
He has been sentenced to two-and-a-half years in a Russian prison.
The 43-year-old purchased Pompey in June 2011 and set out an ambitious five-year plan to transform the then-Championship club.
However, Antonov’s reign lasted just five months and 28 days.
He quit as chairman on November 29 when his company CSI entered administration.
The Football League also hit out at Antonov, claiming he misled officials during the takeover process.
Read Neil Allen’s previous column on Antonov’s tenure by clicking here.