Apple’s long running battle with antitrust regulators could soon cost the company another major source of revenue, as it may no longer be able to collect commissions from purchases made through external payment platforms in the US.

In a recent regulatory filing, Apple acknowledged that it may be forced to stop collecting these fees following its ongoing legal battle over how developers handle payments outside the App Store.

The European Union was among the first to force Apple to allow third party app stores, giving developers alternatives to Apple’s App Store and its 30% commission on purchases, including in app transactions. Similar decisions have since emerged in Japan and Brazil.

The US case took a different approach. Rather than requiring Apple to permit alternative app stores, a court ordered the company to allow developers to direct users toward alternative payment options for in app purchases and subscriptions.

Apple continued charging commissions on transactions involving these external payment systems, however. Developers were reportedly still paying around 27% to Apple, alongside a 3% payment processing fee, effectively limiting the impact of the court’s ruling.

A US judge later determined that Apple’s approach violated the ruling. Apple argued that the court had not established an acceptable commission rate, but subsequently introduced several reduced rates. These included 15% for standard apps, a 30% fee for in app purchases, 10% for certain programs and subscription renewals, and 5% for apps participating in the Small Business Program.

Despite these efforts, Apple now appears to believe it could eventually lose the ability to collect these commissions altogether. People familiar with the matter reportedly expect a significant decline in Apple’s Services revenue over the coming quarters, which could also put pressure on the company’s valuation.