Lawyers for former President Donald Trump say he’s unlikely to secure a bond for the nearly half-billion he and other defendants need to pause a judge’s February ruling in a New York civil fraud case.

They’re asking an appeals court to stay the judgment while Trump challenges it. The judgment, with accrued interest, saddled the defendants with a $464 million tab. In a nearly 5,000-page filing on Monday, Trump’s lawyers wrote that “a bond requirement of this enormous magnitude—effectively requiring cash reserves approaching $1 billion….is unprecedented.”

They called the finding “grossly disproportional” to the offenses Trump and others were found liable for, specifically a decade-long scheme to defraud banks and insurers using overvaluations of properties and Trump’s net worth.

“Very few bonding companies will consider a bond of anything approaching that magnitude,” wrote the lawyers, Alina Habba, Clifford Robert, Christopher Kise and John Sauer.

Trump Organization general counsel Alan Garten wrote in the filing that surety companies are unwilling to accept real estate as collateral. 

Garten said that the company “approached more than 30 surety companies, proposing to pledge as collateral a combination of cash or cash equivalents and unencumbered real estate holdings…[T]he vast majority simply do not have the financial strength to handle a bond of this size. Of those that do, the vast majority are unwilling to accept the risk associated with such a large bond.”

Trump’s filing in the case came one week after he posted a more than $90 million bond in order to appeal another recent legal defeat, a January decision by a federal jury that unanimously concluded he defamed the writer E. Jean Carroll. In that case, he secured a bond through a subsidiary of the insurance giant Chubb.

The filing includes an affidavit from an insurance executive who said he has “been in contact with some of the largest insurance carriers in the world in an effort to try and obtain a bond” for Trump in the case. 

The executive, Gary Giuletti, president of private insurance firm Lockton Companies, wrote that he believes it “is not possible under the circumstances presented” for the defendants to secure a bond.

“Simply put, a bond of this size is rarely, if ever, seen,” Giuletti wrote.

Giuletti testified as an expert witness in Trump’s defense during the fraud trial, describing himself as a longtime friend who is a member of “a bunch of his clubs.” He is also an insurance broker doing business for the Trump Organization.

Judge Arthur Engoron was critical of Giuletti’s testimony during the trial, as well as the defense team’s decision to use him as a witness.

“In its over 20 years on the bench, this Court has never encountered an expert witness who not only was a close personal friend of a party, but also had a personal financial interest in the outcome of the case for which he is being offered as an expert,” Engoron wrote in his Feb. 16 ruling.

A spokesperson for Attorney General Letitia James did not reply to a request for comment. James’ office has said Trump has until March 25 to put up a bond for the entire judgment in order to prevent her office from collecting the damages while he appeals. James has said the state could seek to seize property from Trump if he does not pay the judgment.