Many of the biggest corporations in the U.S. pay few or no taxes on their profits, according to a recent study.

The study by the Institute on Taxation and Economic Policy (ITEP) on the 250 biggest corporations in the U.S. found that these corporations paid an average 20.1 percent in taxes on their profits from 1996-98 — nearly half of the rate of 35 percent required by federal law.

Had all of the companies paid the rate required by law, they would have collectively owed $257 billion. Instead, assorted tax breaks lowered that figure to $159 billion. In fact, some of these corporations even got refund checks from the U.S. Treasury.

Forty-one companies paid less than nothing in federal income taxes in at least one year from 1996 to 1998, according to the report. In those years, the companies reported a total of $25.8 billion in pre-tax U.S. profits. But rather than pay the appropriate $9 billion in federal income taxes, these companies instead enjoyed tax refunds of $3.2 billion.

Almost half of the tax-breaks went to just 25 companies, each getting more than a billion-dollar tax benefit.

The big winner was General Electric, with $6.9 billion in tax breaks over the three years the study looked at. Cisco Systems, the second most valuable company in the U.S., paid no federal income taxes in the latest fiscal year, despite their $2.7 billion in net earnings.

In another example, Texaco reported $3.4 billion in profits and received $304 million in tax rebates. In fact, oil companies, as a group, were the lowest-taxed industry with an effective federal tax rate of 12.3 percent. Only one industry, publishing, paid an effective tax level of 30 percent.

How do these companies get away with it? They use a variety of means to lower their federal income taxes, including depreciation write-offs, tax credits for things like research and oil drilling, and tax breaks for doing business in Puerto Rico. For example, GE continues to slash its tax bills every year through its leasing activities that essentially buy tax breaks from companies that have more than they can use.

The fastest growing tax break for U.S. companies is the use of stock options. By taking the difference between what an employee pays for a stock and what it's worth, 233 of 250 companies lowered their taxes from stock options by a total of $25.8 billion over the last three years, the study found.

It is unfair for multi-billion dollar companies to escape all income taxes. Individual Americans must pay their taxes, and these corporations should too.