Illustration by Marc Rosenthal

When do the words “not guaranteed” actually mean “guaranteed”? Whenever the mortgage giants Fannie Mae and Freddie Mac are involved. The two companies have long been required to tell investors that their securities are not guaranteed by the federal government. But in the financial markets everyone has always assumed that this demurral was just window-dressing, and everyone, it turns out, was right. Last week, when fears of a possible collapse of the two companies threatened to spark a major financial crisis, the Treasury Department and the Federal Reserve quickly came up with a rescue package. What had been an implicit guarantee became an explicit one.

Fannie and Freddie are the duck-billed platypuses of the financial world. They’re profit-driven corporations, owned by shareholders and, in theory, beholden only to them. But they’re also so-called “government-sponsored enterprises,” set up by the state with the explicit mission of fostering homeownership, by buying and selling home mortgages. Unlike ordinary corporations, they’re exempt from most state and local taxes and certain S.E.C. requirements, and they have access to a government credit line. Other G.S.E.s play similar roles in other markets: the Federal Home Loan Banks make loans to banks, credit unions, and thrifts; the Farm Credit Banks facilitate the flow of credit to farmers; and Farmer Mac buys up farm and rural-housing mortgages. In each case, the government saw a hole in the marketplace and chartered a company to fill it.

The G.S.E.s are curious, because there’s no obvious reason for them to exist in the form they do: instead of creating private companies to do all these jobs, the government could just do them itself. In fact, that’s how Fannie Mae got started, back in 1938: originally, it was a government agency endowed with the authority to buy mortgages, in the hope that this would expand the supply of credit to homeowners. It wasn’t until 1968 that Fannie was privatized. (Freddie Mac was created two years later, and was private from the start.) The main reason for the change was surprisingly mundane: accounting. At the time, Lyndon Johnson was concerned about the effect of the Vietnam War on the federal budget. Making Fannie Mae private moved its liabilities off the government’s books, even if, as the recent crisis made clear, the U.S. was still responsible for those debts. It was a bit like what Enron did thirty years later, when it used “special-purpose entities” to move liabilities off its balance sheet.

Making Fannie and Freddie into these weird hybrids may have spruced up the budget, but in the long run it also made it easy for the companies to grow too big, too fast. Because everyone assumed that the government would make good on Fannie’s and Freddie’s debts, they could borrow money more cheaply than their competitors. They used this cheap debt to increase the number of mortgages they bought. Had Fannie and Freddie been ordinary private companies, there would have been a natural check: companies with more debt are usually seen as riskier, and that makes shareholders and bondholders less willing to invest in them. Or, had Fannie and Freddie been government agencies, budget constraints would likely have limited the scope of their lending. Since neither the market nor the state checked their growth, they were able to swell extravagantly. (Regulators might have reined the companies in, but, thanks in part to ardent lobbying by Fannie and Freddie, Congress failed to provide them with sufficient power to do so.)

The result of all this was that the companies reaped the rewards of the private sector while enjoying the security of the public sector. Seemingly insulated from all harm, they became reckless. They constructed a giant pyramid of debt on a very small base of capital (eighty-one billion dollars, by the most recent publicly available figures), and by May, 2008, either owned or guaranteed more than five trillion dollars in mortgages. As a result, even though just a small percentage of Fannie’s and Freddie’s mortgages are delinquent, the potential losses are huge. That’s why, in recent weeks, investors finally lost faith in them.

Whatever their sins, Fannie and Freddie clearly couldn’t be allowed to fail, but that’s no argument for letting them go on as they are. Either they should be forced to make it as private companies or they should be nationalized. Given that their business depends on the promise of government assistance and that their current state remains woeful (despite an upturn in their fortunes late last week), nationalization seems more sensible. If Fannie and Freddie are going to run up a tab and stick taxpayers with the bill, why should shareholders profit?

Beyond that question, though, is a more important one: Do we need Fannie and Freddie at all? Their supposed reason for being is that their ability to borrow money at low rates lowers borrowing costs for homeowners. But a paper by the economist Wayne Passmore, of the Federal Reserve, suggests that in fact Fannie and Freddie have only a small effect on the interest rates that homeowners pay, saving them less than one-tenth of a percentage point. More important, if the last few years have taught us anything, it’s that homeownership is not an unalloyed economic good, and that we should be cautious about using gimmicks to make it more attractive. The government already offers homeowners a subsidy, in the form of a mortgage tax break. Given everything else we could be spending taxpayer money on, does the government really need to be in the mortgage-buying business, too? ♦