The Premier League has turned down prospective club owners "too many times to mention" in the past five years, says chairman Richard Scudamore.
Investors wanting to buy English clubs must pass the owners' and directors' test which came into effect in 2013.
Scudamore told the BBC that the number rejected runs into "at least the tens, probably into the twenties".
"It should be of some reassurance to fans how deep and how hard we work on this. It's very extensive," he added.
The test is designed to make sure owners, directors and officers of clubs meet standards above the legal requirement in order to protect football's reputation and image.