The Fortune

Though he ultimately did not take on the client, the talks expose his enthusiasm for foreign business and his willingness to insert himself in matters rife with potential conflicts. In fact, the Ukrainian bank is entangled in a legal dispute with its former owner who has ties to Ukraine's president and is the subject of a federal investigation in the U.S., Bloomberg wrote.

The former New York City mayor and personal lawyer for President Donald Trump, Giuliani said he was approached by lawyers for Privatbank seeking to recover assets linked to the previous owner. They wanted to know if Giuliani – who had written tweets critical of the man – could assist their civil suit, Giuliani confirmed by phone on Thursday.

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He met with the lawyers at Quinn Emanuel about the case, though they parted ways with no agreement. Quinn Emanuel declined to comment. Privatbank said in an email that it "has not been approached by Mr. Giuliani and has not considered engaging him in any capacity."

Giuliani countered in a May 18 tweet that Ihor Kolomoisky was threatening and defaming the men. He also repeated a claim that Kolomoisky was "super dangerous."

Giuliani's Kolomoisky tweets caught the attention of Privatbank's lawyers as well as lawyers for Ukraine's banking regulator, according to a person familiar with the matter. The regulator's lawyers suggested contacting Giuliani to see if he had any information related to Kolomoisky and misconduct.

Starting in August, Giuliani had two meetings with Quinn Emanuel lawyers. He reviewed a report conducted by the investigative firm Kroll on behalf of Privatbank, Giuliani said this week, saying it outlined problematic activities by several Ukrainian oligarchs.

"We mutually agreed that the case is fantastic," Giuliani said.

The Quinn Emanuel lawyers didn't see any role for Giuliani, since he lacked independent knowledge of Kolomoisky's past conduct, according to the person familiar with the matter. For his part, Giuliani said the timing was not right.