Some of the largest and most profitable Fortune 500 companies are paying little or nothing in state income taxes, according to a new study.

The study, by the advocacy groups Citizens for Tax Justice and the Institute on Taxation and Economic Policy, examined 269 Fortune 500 companies that were profitable every year between 2008 and 2012. Collectively, the companies avoided $73.1 billion in state corporate income tax, according to the study. Ten companies avoided state taxes entirely over the five-year period. The study comes on the heels of another recent report by the same groups that found many Fortune 500 companies also pay extraordinarily low or no federal income tax (see Multinationals Pay Higher Tax Rates Abroad than in U.S.).

The new report found that 90 companies paid no state income tax at all in at least one year, and 38 companies avoided taxes in two or more years. Ten companies, including Boeing, Merck and Rockwell Automation, paid no state income tax at all over the five-year period covered by the study. The average weighted state corporate income tax rate is 6.25 percent, but the 269 companies paid an average rate of just 3.06 percent. The companies examined collectively avoided paying $73.1 billion in state corporate income tax.

Eight companies, including Dupont, International Paper and Tenet Healthcare, paid no net state income tax in at least three years during this five-year period. In 2012 alone, 25 companies paid no state income tax. Another 127 of the companies paid less than half the weighted-average statutory state corporate tax rate that year, meaning that more than half of the companies in the sample paid less than half the average legal state tax rate in that year

The companies in the survey typically operate all over the country but don’t disclose their profits and taxes on a state-by-state basis—so the findings of the report are not able to conclusively say whether specific companies paid any income tax in specific states, only how much the companies have paid to all the states in which they do business. As a result, the figures in the report show only the companies’ nationwide state income taxes. It is also important to note that the tax information reported by corporations in their Securities and Exchange Commission filings and annual reports frequently differs from the tax returns actually filed with the Internal Revenue Service, which are kept confidential.

The study comes at a time when lawmakers in different states are considering outright repeal of the state corporate income tax or proposed lowering the corporate income tax rate, including Idaho, Illinois, Indiana, Kentucky, Maryland, New York, North Carolina, North Dakota and others.

The study provides several recommendations for state corporate income tax reform, including adopting mandatory combined reporting, which treats a parent and its subsidiaries as one corporation for state tax purposes and is the single most important corporate tax reform available to states, adopting a minimum tax to ensure that every profitable company pays at least some income tax and requiring better disclosure of corporate tax payments so state lawmakers know whether companies lobbying them for tax breaks are paying any income taxes to begin with.

To view the study, visit http://ctj.org/90reasons/.