Live Nation said: “The jury’s verdict is not the last word on this matter.”
The company noted it had submitted a request to the court to reject expert testimony related to how the award for damages was calculated.
There were other pending motions that could alter the outcome of the case, it said.
A giant of live music and sports, Live Nation last year organised more than 55,000 concerts worldwide, drawing 159 million attendees.
The verdict could lead to Live Nation and Ticketmaster being broken up and possibly open the way for smaller ticket-sellers and venues to compete with those companies for audiences and live acts.
Increased competition could bring down the price of tickets and see less well-known performers able to book venues more easily.
Morgan Harper, a director at the non-profit economic advocacy organisation American Economic Liberties Project, called the verdict against Live Nation “a historic victory for fans, artists, concert promoters and venue owners who have suffered for decades under the thumb of Ticketmaster’s monopoly”.
John Kwoka, a professor at Northwestern University who previously worked at the US Federal Trade Commission, said the verdict was a warning to large corporations in other industries.
“This shows that it is possible to conduct a focused trial that convinces a court of various anticompetitive acts,” Kwoka said.
Live Nation’s shares fell by more than 6% after Wednesday’s verdict was announced.
As well ordering legal measures to restore competition, Judge Arun Subramanian could impose a financial penalty on the company.
The jury found Ticketmaster had overcharged customers by $1.72 (£1.27) on each ticket sold over a period of several years. That figure is set to be used as the basis for calculating damages.
Live Nation argued throughout the trial that it was not a monopoly and that it competed “fiercely” with rivals in the entertainment space, with sports teams, concert promoters and other venue operators.
