The cab company owner is reportedly mentioned with her husband in FBI warrants used to raid Cohen's home, office and hotel room last week.
That taxi mogul, Yasya Shtayner, with her husband, Semyon Shtayner, manage 22 cabs owned by Cohen in Chicago, along with more than 300 other cabs through their company, Chicago Medallion Management, according to the Chicago Sun-Times.
The company is the largest cab operator in the Windy City.
The newspaper, citing Cook County deed records, reported that Yasya Shtayner obtained eight loans from Fima Shusterman, father of Cohen's wife, Laura, since last August.
The most recent group of four loans, totaling at least $8 million and possibly up to $16 million, were made by Shusterman in March to Shtayner and the two firms she owns.
In August, the newspaper said, Shtayner received four loans for a total of at least $12 million and as much as $24 million from Shusterman.
The loans were secured by collateral made up of three Chicago condos Shtayner owns.
The Shtayners, like Cohen's father-in-law, are immigrants from Ukraine.
Cohen owns 32 taxicab medallions in New York.
His father-in-law, Shusterman, was charged with two other men in 1993 with conspiring to defraud the IRS in connection with his own New York taxi business. He pleaded guilty to a related charge that same year, and was placed on probation for two years.
A man who answered the phone at Shusterman's Manhattan condo at Trump World Tower said, "I know what you want to talk about" when a CNBC reporter identified himself and asked to speak to Shusterman.
"But there's nothing more to talk about. Thank you very much," said the man, who then hung up.
Cohen's lawyer, David Schwartz, did not immediately return a request for comment.
CNBC left a message for Yasya Shtayner at her medallion management company.
Federal prosecutors in New York are investigating Cohen for suspected crimes related to his business dealings, according to court records. He has not been criminally charged.
During the raids last week, FBI agents seized the contents of numerous electronic devices as well as paper documents belonging to Cohen.
Among other things, agents reportedly seized records related to a $130,000 payment that Cohen made to porn star Stormy Daniels shortly before the 2016 presidential election that Trump won.
Daniels has recently said that payment was in exchange for her silence about an affair she claims to have had with Trump in 2006, shortly after the birth of the president's youngest son by first lady Melania Trump.
The White House has denied Trump had sex with Daniels.
On Monday, a judge denied Cohen's and Trump's request that they be allowed to be the ones who first determine what specific records seized from Cohen should not be seen by prosecutors because they are protected by attorney-client privilege.
However, U.S. District Judge Kimba Wood has yet to decide whether she will allow a so-called filter team made of up federal prosecutors not involved in the case to make that determination before Cohen's files can be seen by prosecutors handling the case.
Wood is also considering whether she will appoint an independent watchdog known as a special master to do all or some of that work.
On Wednesday, Wood signed an order allowing Trump's company, the Trump Organization, to be heard going forward in any discussion about the evidence seized from Cohen.
Cohen had been a lawyer for the Trump Organization for a decade.