Richard Scudamore has claimed that the Premier League has rejected prospective club owners "too many times to mention" in the past five years.
Investors wanting to buy English clubs must pass the owners' and directors' test, which came into effect in 2013.
The test stipulates that owners, directors and officers of clubs meet standards above the legal requirement in order to protect football's reputation and image.
However, there have been a number of protests among fans of EFL clubs against unpopular owners, with some suggesting that the test is not doing its job.
Asked how many times prospective owners have been turned down, the Premier League chairman told BBC Sport: "Too many times to mention. I wouldn't have a count of them but it would run into the tens and probably into the twenties.
"It's a very complex process. We have business intelligence companies that operate all around the world and we, the Premier League, spend an awful lot of money on this, it's a costly business.
"We delve right to the bottom and manage to find out things that the investment banks don't seem to be able to find out sometimes because we have very deep and resourceful intelligence networks.
"It should be of some reassurance to fans how deep and how hard we look at this, it's very extensive because ultimately they are only custodians for as long as they are here, the clubs are far more than just business assets."
On the subject of the EFL, Scudamore said: "I'm not going to talk about individual cases but we work closely with the Football League on all of these matters and help support them financially with their investigations as well because we want the game in England to run to very similar tests.
"So we do have an influence, ultimately though the board of the Football League have their own decision to make."
The 20 Premier League clubs will vote on changes to the test at next month's annual shareholder meeting.
