• The judge presiding over former President Donald Trump's civil fraud trial harshly questioned the credibility of an expert defense witness, New York University Accounting Professor Eli Bartov.
• Manhattan Supreme Court Judge Arthur Engoron wrote that the only thing Bartov's testimony proves "is that for a million or so dollars, some experts will say whatever you want them to say."
• Bartov told CNBC he was "shocked" by the judge's remarks and denied that his payment played a role in his assessment.

The judge presiding over the high-stakes civil business fraud trial of former President Donald Trump harshly questioned the credibility of a key expert defense witness, suggesting his testimony was influenced by his nearly $900,000 fee.

The expert, New York University Accounting Professor Eli Bartov, told CNBC he was "shocked" by the judge's remarks and denied that his payment played a role in his assessment.

Manhattan Supreme Court Judge Arthur Engoron slammed Bartov in a Monday evening ruling denying the defendants' latest request for a directed verdict in the $250 million case.

"Bartov is a tenured professor, but all that his testimony proves is that for a million or so dollars, some experts will say whatever you want them to say," Engoron wrote in the three-page ruling.

It is common for experts to be paid by the party asking for their involvement in a lawsuit, but opposing parties — or in this case, a judge — can use that compensation to question the expert's credibility.

"The most glaring flaw" in the defendants' bid to scrap the case for lack of evidence, Engoron wrote, is their assumption that their experts' testimony "is true and accurate, or at least that the Court, as the trier of fact, will accept it as true and accurate."

The judge wrote that Bartov's "overarching point" was that the financial statements at the heart of the case "were accurate in every respect."

But Engoron noted that he had already found that those financial records "contained numerous obvious errors" before the trial even began. "By doggedly attempting to justify every misstatement, Professor Bartov lost all credibility," Engoron wrote.

Bartov said that Engoron's description of his testimony was a "complete mischaracterization."

Bartov said his testimony acknowledged that the financial statements contained errors, such as the valuation of Trump's triplex apartment in Manhattan's Trump Tower.

But he found those errors to be inadvertent, rather than fraudulent, he said.

"I'm shocked that the judge mischaracterized my testimony in this way," Bartov said.

New York Attorney General Letitia James' office said Trump's financial records reported the Manhattan triplex as being 30,000 square feet, nearly three times its actual size. The apartment in 2015 was valued at $327 million, more than triple the value of the most expensive apartment ever sold in New York City, according to the AG's office.

Engoron's pretrial ruling found Trump and his co-defendants liable for fraudulently misstating the values of real estate properties and other key assets, the central claim of the civil lawsuit brought by James.

In Monday's decision, Engoron noted that the defendants have made at least five attempts for a directed verdict in the case, all of which have been denied.

Trump, in a lengthy statement on Truth Social, blasted Engoron's latest ruling. He repeated various claims that he has frequently put forward in defense of the financial statements, including claiming that his Palm Beach resort home Mar-a-Lago is worth up to $1.8 billion.

Trump also defended Bartov against Engoron's criticisms.

"Judge Engoron challenges the highly respected Expert Witness for receiving fees, which is standard and accepted practice for Expert Witnesses," Trump wrote. "The ignorant Judge did not even try to listen to the Expert witness. This is a great insult to a man of impeccable character and qualifications."

Bartov rejected Engoron's insinuation that he was swayed by money. "The fee played no role," he said.

The professor said in his trial testimony, and in a deposition over the summer, that he was being compensated at a rate of $1,350 an hour for his involvement with the defense.

He said on the stand that he logged 650 billable hours, which adds up to $877,500 in compensation.

He also noted that Save America, the political action committee backing Trump's 2024 presidential campaign, had paid some of those bills, while the Trump Organization paid the rest.

Bartov told CNBC that he had charged the same hourly rate in other cases, adding that he was "very efficient" with his time in this case because he had worked without the support of a consulting firm.

The ten-and-a-half week trial was held to determine damages and resolve James' other claims of wrongdoing against Trump, his adult sons Donald Trump, Jr. and Eric Trump, the Trump Organization and its top executives.

James seeks $250 million in damages and wants to permanently bar Trump and his sons from running another New York business.

The parties are set to deliver closing arguments on Jan. 11.