A major fight in the Live Nation antitrust case has erupted over two simple words: “retained amount.”

Lawyers for the state attorneys general pressing the monopoly case say the phrase is just a technical term—used by an expert economist to calculate the alleged harm Ticketmaster caused by overcharging customers and behaving like a monopoly.

Live Nation’s lawyers see it very differently. They argue the term is more than legal jargon—it’s a made-up concept from plaintiffs worried their case is slipping away. According to Live Nation attorney Alfred Pfeiffer, the phrase is evidence that a key government witness misled the jury to prop up what he calls a paper-thin legal strategy misrepresenting both Ticketmaster and how it sets fees.

The dispute centers on Dr. Rosa Abrantes-Metz, the state’s key damages expert. Hired by the Department of Justice, the NYU-affiliated economist was tasked with modeling competition in the ticketing market. Live Nation is now asking the court to strike her testimony entirely, calling it “false and misleading.” Plaintiffs counter that this is a “drastic remedy” built on distortions that would gut their damages case.

Typically, expert testimony is challenged before trial through a Daubert motion—named after the 1993 Supreme Court case that sets standards for admissibility. The fact that Live Nation is trying to exclude Abrantes-Metz’s testimony after she has already testified underscores how heated the case has become as it nears the finish line.

At the center of the clash is her “retained amount” concept. Abrantes-Metz defines “retained amount” as the portion of the ticket price that Ticketmaster keeps. Her analysis finds Ticketmaster retains, on average, $2.30 more per ticket than rival AXS. She calculates damages by applying that difference across every Ticketmaster sale from 2017 to 2024—potentially adding up to hundreds of millions, if not billions, of dollars.

Live Nation argues the model is fundamentally flawed because it ignores upfront payments Ticketmaster makes to secure clients—costs the company says are essential to understanding its pricing. Abrantes-Metz acknowledges her model excludes those payments, but notes it also excludes similar costs from AXS.

Her reasoning: the model was never intended to measure net profit. “To arrive at that,” she wrote in an April 3 declaration, “one would of course deduct all manner of expenses… That number could be much lower… it could even be negative. But it is not economically relevant.”

Still, Live Nation says that omission is critical. If Ticketmaster pays more upfront to secure more clients, they argue, those costs should be reflected in any damages model.

The fight has intensified in recent days after Live Nation filed a motion accusing the economist of perjury.. In a sworn declaration, Abrantes-Metz clarified that “retained amount” was her own construct and not a term used by Ticketmaster internally. But at trial, she testified that she used company data and followed defendants’ instructions to calculate the company’s “retained amount” — language Live Nation says could mislead jurors into thinking the metric came from Ticketmaster itself.

“That indicates a conscious, premeditated plan to give testimony creating the false impression,” Pfeiffer wrote, even raising the possibility of perjury.

Plaintiffs strongly reject that claim. Lead counsel Jeffrey Kessler argues that perjury requires a “willful, material falsehood—not ambiguous answers to confusing questions under the pressure of cross-examination.” Abrantes-Metz herself pushed back forcefully, saying, “I would never lie or fabricate anything… lying in a court of law would be anathema to my personal code of ethics.”

Even if unintentional, Live Nation contends the confusion is disqualifying—pointing to her admission that she “may have misspoken or been unclear.” More broadly, they argue that excluding upfront payments isn’t a minor omission but a “fundamental error.”

Plaintiffs say this is simply a classic battle of experts. “This argument goes to weight, not admissibility,” Kessler wrote.

The issue came to a head in a brief hearing last week, where Judge Arun Subramanian denied the states’ request for more time to respond. “I honestly want to make sure the plaintiffs are taking this seriously,” he said.

Abrantes-Metz was back in court Monday answering more questions and Subramanian has yet to rule on whether to strike the testimony.

The stakes are high. If Abrantes-Metz’s testimony stands, Live Nation will likely continue attacking it before the jury as unreliable rather than inadmissible. If it’s struck, plaintiffs acknowledge it would eliminate “the only expert testimony quantifying harm to fans”—leaving the government without a clear damages model.