Apple was denied permission on Thursday to appeal a London tribunal’s ruling that it abused its dominant position by charging app developers unfair commissions, though the company may still seek to challenge the decision at a higher court.

The Competition Appeal Tribunal (CAT) last month found that Apple had abused its market dominance by restricting competition in app distribution and by charging “excessive and unfair” commission fees.

The ruling leaves Apple—already under growing regulatory scrutiny in the U.S. and Europe over its developer fees—facing a potential liability of more than £1 billion ($1.3 billion).

While the CAT refused Apple’s request to appeal, the company can still apply directly to the UK Court of Appeal. Apple’s lawyers asked the tribunal for 21 days to file any such application.