The case decided on Friday alleged that Parnas and an associate made illegal donations through a corporate entity to Republican political committees in 2018, including a $325,000 donation to America First Action, a super PAC supporting former President Donald Trump.
Giuliani has acted as Trump’s personal lawyer.
Another part of the case said Parnas used the wealth of a Russian financier, Andrey Muraviev, to make donations to US politicians, ostensibly in support of an effort to launch a legal, recreational cannabis business.
Parnas, 49, was convicted of all counts.
The trial has drawn attention because of the role Parnas and Belarus-born US citizen Igor Fruman played in helping Giuliani, who was Trump’s personal lawyer while he held office, to investigate Joe Biden during the 2020 presidential campaign. Biden won the election, denying Trump a second term.
The case in federal court in Manhattan also provided a glimpse into the inner workings of political fundraising in the US.
“You saw the wires from Muraviev,” Assistant US Attorney Hagan Scotten told the jury during closing arguments on Thursday. “You saw how that money came out on the other side, finding its way into American elections, where the defendants thought they had bought influence to further their business.”
Parnas’s defence lawyers countered that Muraviev’s funds went towards business investments, not campaign contributions, and that the donation to the pro-Trump group was from a company founded by Parnas and broke no laws.
In his closing statement, Parnas’s lawyer, Joseph Bondy, characterised his client as a passionate proponent of cannabis legalisation who was “in well over his head”. He argued that Muraviev’s money funded business operations, not campaign contributions.
Muraviev associate, Andrey Kukushkin, a California resident who was tried alongside Parnas, was also found guilty of campaign finance violations.
Giuliani, a US prosecutor before he became New York mayor in 1994, has not been charged with any crimes and has denied wrongdoing.
Giuliani and Trump were sparsely mentioned during the trial, but a photograph featuring Parnas with Florida Governor Ron DeSantis, a Republican, was one of the first exhibits shown to jurors during closing arguments and a video of Giuliani with Parnas was among exhibits jurors could view during deliberations.
DeSantis was among those who received campaign contributions that prosecutors said were traced to $1m that Parnas and Fruman received from Muraviev, who has been involved in several US cannabis ventures.
Fruman, who lives in Florida, pleaded guilty to one count of soliciting campaign contributions from a foreign national. His sentencing is scheduled for January 21.