Mawhinney and the Football League board addressed several issues
Football League clubs will have to disclose the identities of their owners after a ruling by the League's board.
"As of today, it will be the policy of the board," a statement read on the Football League's website read.
Chairman Lord Mawhinney told BBC Radio 5 live: "It seems reasonable we ought to know who the beneficial owners are."
The issue was discussed at a League board meeting on Thursday, with the ownership of both Notts County and Leeds United under the spotlight.
Mawhinney feels it is important for the Football League to know the identity of the backers of their member clubs.
After the meeting, which also discussed the League's Fit and Proper Persons test as well as club ownership in general, a League statement read: "It was unanimously agreed that it will be the policy of the Board to insist that it is informed, with supporting evidence provided, of the ultimate beneficial owners of all Football League clubs."
League Two side County were taken over during the summer by Munto Finance, a private overseas investment trust.
The Shafi and Hyat families have been named as investors but other investors remain anonymous and, last week, former Pakistan prime minister Dr Moeen Qureshi denied any involvement.
"Meetings to clarify a few outstanding issues will occur during the next few days, with a view to concluding matters in the near future," the League statement added.
Leeds United were also discussed at the board meeting after question marks were raised over their ownership, with the statement adding: "The League has written to the club seeking clarification."
Meanwhile, the League sought clarification from Queens Park Rangers co-owner Flavio Briatore over a number of issues related to the Fit and Proper Persons Test.
Briatore was recently banned from FIA-sanctioned motorsport events after an Formula 1 race-fixing scandal.
Mawhinney added: "The law of the land complicates issues because people are allowed to put their money offshore and in many places that accords them anonymity that makes scrutiny very difficult.
"You don't defy the law of the land - if people want to do that, they can do it but If you want to place your money offshore and you want to have the anonymity then don't come and ask if you can play in my league because I think all of our clubs should know basically the structure of the clubs they are playing against.
"It's our league and, if we decide we want to know certain information before we allow people play in our league, I think we are probably entitled to do that but I have been taking some serious legal advice on this subject.
"I have been extremely careful in my remarks not to speak about specific clubs. I'm talking about a policy decision, a general principle. Having given this a lot of thought in recent weeks, I am comfortable in my position on this matter."
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.