Taking up a key issue in housing finance reform, one within his control as the new director of the Federal Housing Finance Agency, Mark Calabria told a conference recently that Fannie Mae and Freddie Mac must in the future have a strong capital position.

He’s absolutely right. And this would be in vivid contrast to the 0.2% capital ratio they have now.

Calabria stated that “all large, systemically important financial institutions should be well capitalized,” specifically including Fannie and Freddie. “That would seem nondebatable at this point.”

Indeed it does. No one can plausibly disagree.

But what is the number? What is the explicit capital ratio which would implement Calabria’s excellent principle?

I believe his remarks in effect gave us the answer by asking the question in this pertinent way: “How do we level the playing field to where all large financial institutions have similar capital” so that Fannie and Freddie do not have “lower standards than everybody else”?

The answer to this well-framed question is obvious: Give the government-sponsored enterprises the same capital requirement for mortgage risk that everybody else has. In short, the answer is 4%. This is the internationally recognized standard for mortgage risk, which represents virtually all of Fannie and Freddie’s assets. The FHFA should, in my view, immediately establish a minimum capital requirement for Fannie and Freddie of tangible equity equal to 4% of total assets.

Considering them on a combined basis, 4% of Fannie and Freddie’s assets of $5.5 trillion results in a required capital of $220 billion between the two of them. That is 22 times their current capital and $210 billion more capital than they’ve got right now.

Naturally, Fannie and Freddie cannot retain or raise any more capital while subject to the “profit sweep” to the Treasury, but let us suppose the senior preferred stock purchase agreements between the Treasury and the FHFA as conservator could be renegotiated. This outcome would not be unreasonable, since the Treasury now has an internal rate of return on its preferred stock investment of about 12% — which is pretty good — and much better than the original 10% agreement. On top of that, Treasury still has warrants to acquire 79.9% of Fannie and Freddie’s common stock at an exercise price of virtually zero (0.001 cents per share). That could be a nice pop for the taxpayers on top of the 12% average annual return.

As President Trump’s March 27 memorandum on housing finance reform makes clear, as part of any renegotiation, Fannie and Freddie will need to pay the Treasury for its ongoing credit support, implicit or otherwise. This should absolutely be required.

How much in fees should they pay? That is debatable, to be sure, but definitely not nothing. We might consider that the lowest-rated banks on the FDIC’s deposit insurance fee table pay a range of 16 to 30 basis points of total liabilities per year for their government guarantee. Let’s give the critically undercapitalized Fannie and Freddie the benefit of the doubt and assume the lowest end of that range: a fee to the Treasury of 16 basis points.

What kind of return on equity could a Fannie and Freddie capitalized at 4% then expect? Here’s one estimate. Fannie and Freddie’s combined net profits for the first quarter of 2019 were $3.8 billion. That annualized is $15.2 billion — let’s call it $16 billion. Subtract from that the 16-basis-point fee to the Treasury assessed on liabilities, which after tax would be $7 billion. Add the fact that they would have $210 billion more cash worth 2.5%, or approximately $4 billion, after tax. In sum, that gives $13 billion in net profit pro forma, or an ROE of about 6%. If the fee to Treasury were dropped to 10 basis points, the pro forma ROE would rise to a little over 7%.

That seems like a reasonable starting range. It compares to the five-year average ROE of U.S. banks of 9.6%. From the 6% to 7% range, there are lots of actions in pricing, greater efficiency and improved methods for management to pursue. But running at hyperleverage as in the old days and in the conservatorship days would not be possible. That would move the mortgage market toward the more competitive state that Calabria correctly envisions.

What should happen next? The FHFA should set a 4% capital standard for Fannie and Freddie. The Financial Stability Oversight Council should designate Fannie and Freddie as the “systemically important financial institutions” they so obviously are, treating them the same as others of their size. The Treasury should exercise as a gain for the taxpayers its warrants for their common stock, removing any uncertainty about the warrants. When capital has become sufficient, the FHFA should end the conservatorships and implement regulation that ensures that Fannie and Freddie’s credit risk stays controlled and tracks how the more competitive, less GSE-centric mortgage system evolves.

Congress does not have to do anything in this scenario. That is good, because it is highly unlikely that it will do anything.