The last time the nation’s tax code was overhauled, in 1986, Congress tried to end a big corporate giveaway.

But this valuable perk — the ability to finance a variety of business projects cheaply with bonds that are exempt from federal taxes — has not only endured, it has grown, in what amounts to a stealth subsidy for private enterprise.

A winery in North Carolina, a golf resort in Puerto Rico and a Corvette museum in Kentucky, as well as the Barclays Center in Brooklyn and the offices of both the Goldman Sachs Group and Bank of America Tower in New York — all of these projects, and many more, have been built using the tax-exempt bonds that are more conventionally used by cities and states to pay for roads, bridges and schools.

In all, more than $65 billion of these bonds have been issued by state and local governments on behalf of corporations since 2003, according to an analysis of Bloomberg bond data by The . During that period, the single biggest beneficiary of such securities was the Chevron Corp., which last year reported a profit of $26 billion.

At a time when Washington is rent by the politics of taxes and deficits, select companies are enjoying a tax break normally reserved for public works. This style of financing, called "qualified private activity bonds," saves businesses money, because they can borrow at relatively low interest rates. But those savings come at the expense of American taxpayers, because the interest paid to bondholders is exempt from taxes. What is more, the projects are often structured so companies can avoid paying state sales taxes on new equipment and, at times, avoid local property taxes.

Budget analysts say these bonds amount to a government subsidy, in the form of forgone tax revenue. While it is difficult to calculate the precise dollar amount of the subsidy, given the number and variety of these bonds, experts say the annual cost to federal taxpayers could run into the billions.

"The federal government doesn’t cut a check for this, but it costs the government in terms of lower tax revenue," said Lisa Washburn, a managing director at Municipal Market Advisors, an independent municipal research firm in Concord, Mass., that assisted The Times with its analysis. "If these companies were to issue taxable bonds instead, then the federal government would receive tax revenues on them."

Washburn added that the gain to companies, and bond buyers, can be big and long-lasting.

Chevron used most of its federally tax-free borrowings to expand a refinery in Pascagoula, Miss. Archer Daniels Midland, the agribusiness giant, used about $180 million in tax-exempt bonds to improve its grain-processing facilities in Indiana and Iowa. Alcoa raised $250 million to renovate an aluminum plant in Iowa.

Such financing arrangements are now worrying some state and local officials. Many are concerned that the budget battles in Washington will mean less federal money for them, and that the federal government might try to limit the scope of their own tax-free financing.

Some of the subsidized business projects are almost indistinguishable from public works. American Airlines, for instance, another big user of tax-exempt bonds over the last decade, used $1.3 billion of these securities to finance a new terminal at Kennedy International Airport. That terminal is owned by the City of New York; American is the builder, the borrower and a tenant.

As political controversy over the federal deficit has mounted, some fiscal experts have taken aim at this sort of tax-exempt borrowing. The team at the Bipartisan Policy Center led by Alice M. Rivlin, a former member of the Federal Reserve, and Pete V. Domenici, the former Republican senator, has called for ending it. A spokeswoman for the center said that such a change could bring in $50 billion for the federal government over 10 years.

The Obama administration would take a different approach, capping the value of the tax break that wealthy bond buyers enjoy, whether they buy private activity bonds or conventional municipal bonds. Some of the bonds in the Times analysis are subject to the alternative minimum tax, but taxpayers who incur the AMT typically don’t buy those bonds.

It was Rivlin who, as founding director of the Congressional Budget Office, issued one of the first major reports on private activity bonds, which the report said were invented by local officials in Mississippi who were eager to attract business during the Great Depression.

In a 1981 report, Rivlin found that the bonds were in much wider use than previously understood. Companies were using the federal subsidy to build Kmarts, McDonald’s restaurants, private golf courses and tennis clubs — even a topless bar and an adult bookstore in Philadelphia.

"These trends have cast into sharp relief the questions concerning the public purpose" of the subsidy, Rivlin wrote at the time. "So far, federal legislation has left the definition of ‘public purpose’ to state and local governments."

In 1986, in a sweeping tax reform signed by President Ronald Reagan, Congress set limits on private activity bonds, giving each state a yearly allotment. Some projects, like airports and wharves, were not subject to the yearly limits. Others could not be financed with tax-exempt bonds at all, including golf courses, stadiums, hotels, massage parlors and tanning salons.

But over time, Reagan-era concerns about budget deficits faded, and so did some of the limits on tax-exempt private activity bonds. The Government Accountability Office reported in 2008 that use had risen to a record high and that once-forbidden projects like stadiums, hotels and golf courses were back.

"It is not clear whether facilities like these provide public benefits to federal taxpayers," the GAO stated in its report.

In the years since 1986, Congress had lifted the caps on some states’ or cities’ allotments, often in response to natural disasters and other emergencies.

After the terrorist attacks on the World Trade Center in 2001, for example, Congress approved $8 billion worth of tax-exempt Liberty Bonds, which were in addition to New York state’s normal allotment and could be used to keep companies from moving out of the neighborhood near ground zero. Goldman Sachs used around $1.6 billion of tax-exempt bonds under the program to help pay for its headquarters in Lower Manhattan. In a related program, Goldman agreed to a goal to keep 8,900 jobs in the city but has not met that level for the last three years, according to public records.

A spokesman for Goldman Sachs did not dispute that its jobs levels have been below 8,900 but said the bank was meeting its obligations.The Liberty Bond program allowed for a limited amount of tax-exempt financing for projects beyond Lower Manhattan. That’s how One Bryant Park LLC was able to use $650 million of tax-exempt bonds to build the Bank of America Tower in Midtown.

In 2005, Congress created a similar program to spur rebuilding in areas of Louisiana, Alabama and Mississippi that were ravaged by Hurricane Katrina. The Times’ data show that much of the bond proceeds went to the oil and gas industry, or to showcase projects like hotels or the Superdome.

In 2008, Congress passed the Heartland Disaster Tax Relief Act, a bond program to help 10 Midwestern states hit by flooding and tornadoes. The goal was to help businesses rebuild their destroyed property. But by the time the program was set to expire at the end of last year, the criteria had been expanded to include new businesses.

One of those businesses was Orascom Construction Industries of Egypt, which raised $1.2 billion of tax-exempt bonds to build a fertilizer plant in Iowa. Another was the Fatima Group of Pakistan. In December, a Fatima subsidiary raised $1.3 billion, tax exempt, to build a fertilizer plant in Mount Vernon, Ind.

But weeks later, Indiana received alarming news: Pentagon officials said that fertilizer from Fatima’s operations in Pakistan had been turning up in Afghanistan, in homemade bombs used against U.S. troops. Gov. Mike Pence of Indiana has delayed the project while the Defense Department investigates. The $1.3 billion is now sitting in escrow, and will have to go back to the bond buyers if the project is rejected.

© 2013 The New York Times Company