Regal Entertainment, the country’s second-largest theater chain, will no longer sell tickets to the movies it exhibits on Atom Tickets, Variety has learned.

The two companies quietly ended their agreement in July when Regal opted not to renew its deal with the ticketer. The partnership started in 2016.

“Atom has more than 60 exhibitors on our network including the largest chain in the country, AMC, and our newest partner, Cinemark,” a spokesperson for Atom said in a statement to Variety. “Though we’re disappointed in Regal’s move, we are more concerned with their lack of support for aggregators. We believe that movie fans should have choice when it comes to deciding where they buy their movie tickets. Thanks to our network exhibition partners, we are happy to share that 90% of movie-goers live within 5 miles of an Atom supported theater.”

Regal did not respond to a request for comment. However, a source with knowledge of the situation said the chain is beginning to move away from third-party sellers. It is also preparing to launch its own subscription service, following in the footsteps of AMC and Cinemark, which have their own monthly plans for frequent moviegoers.

The news of Regal’s departure comes two months after Atom announced that it had partnered with Cinemark and would begin selling tickets to its 340 U.S. locations on its app. Atom is also available in several other major theater chains, including AMC, Landmark and National Amusements’ Showcase Cinemas.

Atom Tickets was founded in 2014 with an investor group that included Lionsgate, Disney, 20th Century Fox Film and Fidelity. The service allows customers to buy tickets in advance, as well as coordinate moviegoing with friends and pre-order concessions.

Rebecca Rubin contributed to this report.