A monumental ruling that could upend former President Donald Trump‘s business empire in New York is on hold while the judge tries to figure out if former Trump Organization Chief Financial Officer Allen Weisselberg lied from the witness stand.

Judge Arthur Engoron told lawyers for Mr. Trump and New York Attorney General Letitia James that he wants to know more about reported plea talks between Manhattan District Attorney Alvin Bragg and Mr. Weisselberg because of alleged false testimony last October.

Judge Engoron said it is important that he get the full scope of Mr. Weisselberg‘s testimony, which focused on the size of Mr. Trump‘s apartment at Trump Tower, before he issues his ruling.

“As the presiding magistrate, the trier of fact, and the judge of credibility, I of course want to know whether Mr. Weisselberg is now changing his tune, and whether he is admitting he lied under oath in my courtroom at this trial,” the judge wrote in the email, which was posted in the court’s docket.

The judge gave lawyers until the end of business Wednesday to tell him what they know about the Weisselberg matter, so long as it does not violate their professional ethics or obligations.

“I would also appreciate knowing how you think I should address this matter, if at all, including the timing of the final decision,” the judge wrote.

Judge Engoron is set to deliver a blockbuster ruling on whether Mr. Trump submitted false financial statements to gain favorable terms on loans and insurance.

Ms. James said the Trump Organization did this for years and should pay $370 million. She also wants to bar the Trump family from doing business in New York.

Mr. Trump says he followed normal real estate practices and that banks were happy to do business with him because they were repaid in full and made money on the loans.

Mr. Trump visited the Manhattan courtroom sporadically during the lengthy trial and unloaded on Judge Engoron and Ms. James in courthouse rants and social media posts, characterizing both officials as Democrats out to thwart his presidential bid.

At one point, Judge Engoron issued a gag order preventing Mr. Trump from verbally attacking his court clerk or other staff.

The judge was expected to decide the case by the end of January. The Weisselberg matter appears to be the main sticking point as the ruling slips into mid-February.

During the weeks-long trial, Mr. Weisselberg attempted to explain at the trial why Mr. Trump‘s Fifth Avenue apartment was listed on statements of financial condition as 30,000 square feet, when it was less than 11,000 square feet.

“It was almost de minimis relative to his net worth, so I didn’t really focus on it,” Mr. Weisselberg testified. “I never even thought about the apartment.”

Forbes magazine, however, said Mr. Weisselberg had tried to convince the magazine that the apartment was as big as the financial statements stated, indicating he did think about the matter.

“Forbes was right — the triplex was actually only 10,996, right?” a state lawyer pressed him at trial.

“Right,” Mr. Weisselberg said.

• Tom Howell Jr. can be reached at thowell@washingtontimes.com.