Andrei Kozlov, who oversaw bank licensing and led a campaign against corruption and money laundering, was shot dead along with his driver in September 2006. Kozlov had revoked licenses from banks run by Frenkel.
"The jury has unanimously decided that Frenkel was guilty and deserves no leniency. The jury also brought guilty verdicts against another six suspects in the case," Anna Usachyova said.
The prosecution said it was happy with the jury's decision.
Frenkel, who has been in custody since January 2007, along with restaurant owner Liana Askerova, whose testimony led to his arrest, and Boris Shafrai, a Ukrainian businessman, were all accused of organizing the murder.
Another four people were also accused of involvement in the killing. Another suspect has gone into hiding and is currently on an international wanted list.
Investigators said Frenkel paid $300,000 for the murder, and that the perpetrators received between $3,000 and $8,500 with the intermediaries receiving over $80,000 each.
The defense said they would appeal the verdict following sentencing.
