Newcastle and Manchester City are considering legal action against new rules to restrict related-party sponsorship that were approved by the Premier League on Tuesday.
Both clubs voted against a new requirement for all new commercial deals to be submitted to the Premier League Board for approval, and are now looking at other options for blocking rules they consider to be anti-competitive and open to conflicts of interest.
The tighter rules are a direct response to the Saudi-funded takeover of Newcastle in October, when the Premier League also introduced a temporary ban on any new related-party deals, although that has now been lifted.