Former President Donald Trump was in court for his New York civil fraud trial on Thursday where an accounting expert sought to bolster the defense argument that company valuations are a highly subjective process. Trump cast the trial as "corrupt" in brief comments to reporters before entering the courtroom, criticizing the judge presiding over the trial, Arthur Engoron, and New York attorney general Letitia James, who brought the case against him. "We did absolutely nothing wrong," the former president said. Trump also praised defense accounting expert Eli Bartov, who testified Thursday. A professor of accounting at New York University's Stern School of Business, Bartov said that accounting standards offer wide latitude for valuation calculation methods used on personal financial statements. The former president's appearance in court comes one day after the fourth GOP presidential debate, which Trump skipped. The former president, who is leading the Republican primary, declined to answer questions about the GOP race Thursday morning as he criticized the attorney general's civil case against him. He later told reporters he attended court Thursday to make sure the public "gets the true story." The high-stakes civil case strikes at the heart of Trump's brand – his real estate empire. New York Attorney General Letitia James is suing Trump for $250 million and seeking to bar him from doing business in the state. Judge Engoron has already ruled that Trump and his co-defendants were liable for fraud. The thrust of the Trump defense is that the financial statements were not misleading and that different people can come up with different values for the same property. The defense has argued that there was no intent to defraud banks or insurers, in part because the Trump family relied on accountants, and that any differences in values on the properties were not meaningful. "My main finding is that there is no evidence whatsoever for any accounting fraud," Bartov testified Thursday. "On another end, my analysis shows that the statements of financial condition were not materially mistaken." "So in your expert opinion, the AG's claims have no merit?" Engoron asked. "That is absolutely my opinion. Absolutely." Bartov said. While he acknowledged there were errors in Trump's financial statements, noting that the price of Trump's triplex apartment at Trump Tower was inflated, Bartov maintained, "Errors like that are not unusual." Bartov, who argued Trump's brand is worth $3 billion, said he'd searched for clues that there was something wrong in the statements or reports but he "couldn't find a single provision that was violated. I couldn't find one." Trump attorney Jesus Suarez also walked Bartov through a Deutsche Bank credit report showing Trump and Deutsche Bank used different cap rates – the amount of return a real estate asset is expected to generate in a year – to determine the value on Trump Tower in 2013. "The AG interpreted this as fraud. This is not fraud. This is obvious. This is an expected difference," Bartov said. In one tense moment, Bartov took issue with an objection from a lawyer for the attorney general, Louis Solomon. When Solomon objected, saying part of Bartov's testimony was now outside the scope of his expertise because he's not a banker, Bartov shouted at him, "Shame on yourself, talking to me like that!" "You make up allegations. I'm here to tell the truth," Bartov said. "You ought to be ashamed of yourself." In September, before the trial began, Engoron ruled that the Trumps engaged in "persistent and repeated fraud" by inflating the value of assets on the financial statements.The state is attempting to prove six other claims, including conspiracy, falsifying business records, issuing false financial statements, and insurance fraud. "Donald Trump engaged in years of financial fraud and enriched himself and his family," James, who was not in court Thursday, posted on X. "We have already proven the massive scale of his fraud. No matter how much he lies, the facts don't." The attorney general's office had objected to Bartov's testimony, arguing his extensive testimony about the complaint was not relevant because he was not addressing evidence admitted at trial. Also on Thursday, a New York appeals court agreed to stop the cancellation of Trump's business certificates until after the civil fraud trial and any appeals are completed – a continuation of an earlier ruling by a single appeals court judge at the start of the trial. Trump, outside the courtroom, hailed the decision as a "very good ruling" moments after it was released. His attorney, Chris Kise, similarly told CNN the ruling "helps pave the way for a much needed, and deliberative, review of the trial court's many errors." The attorney general's office had told the appeals court it did not object to pausing the cancellation of the business certificates. Trump is expected to testify again in the trial on Monday. Alina Habba, an attorney for the former president, told reporters outside the courthouse Thursday that Trump will do so despite her advice not to because he's under a gag order in the case. "He still wants to take the stand even though my advice is at this point you should never take the stand with a gag order. But he is so firmly against what is happening in this court," Habba said Thursday. The former president is barred from discussing court staff after a New York appellate court reinstated his gag order late last month. Engoron originally issued the order barring Trump from making public statements about his court's staff after Trump made numerous comments about a clerk, who Trump says is biased against him. — CNN