Apple is using every tool at its disposal to fight Epic Games' antitrust lawsuit over the App Store, and that apparently includes recruiting one of Epic's rivals... or rather, trying to recruit one of them. Apple and Valve have submitted a joint court letter indicating that they'd failed to reach agreements over a subpoena requesting Steam data.
Apple wanted info on Steam's yearly financial performance, plus availability details for 436 titles, to help gauge the total market size for Epic's available digital release channels. In theory, this would show there was plenty of competition.
Valve balked at the request, however, claiming that the request was over-broad, asked for "highly confidential" info and would force an "extraordinary burden" on staff. Third parties control their pricing and in-game content on Steam, and Apple is simply using Steam as a shortcut to that data, Valve added. It also questioned Apple's need for the info in the first place, noting that Valve didn't compete in mobile app stores and that a request for 436 games "does not show" the scope of the market.
The Steam developer added that Apple appeared to contradict its past self. It previously argued that the market involved platforms where Fortnite was available, but was now focusing on the mobile world.
The judge in the lawsuit has yet to decide in favor of either Apple or Valve following this letter. This does illustrate Apple's strategy, though. If Valve's refusal stands, it also leaves Apple without some of the data it hoped to use in court. While there's no guarantee the data would help, Apple might have to rely on alternative support if it's going to fend off Epic's claims in the US and abroad.