Just how much do companies actually pay in corporate income taxes? And how does your organization’s tax rate stack up?

According to a new study of the S&P 500 companies, the range of variation in tax burdens is huge, with businesses paying anything from close to zero to more than 390 percent.

The study was commissioned by BusinessWeek and conducted by the magazine’s sister company, Capital IQ. The highest effective rate — a four-year average of 391.3 percent, to be precise — was paid by identity protection firm VeriSign. Fidelity National Information Services averaged 254.8 percent, and Zions Bancorporation 226.1.

Now, it’s hard to see how businesses can pay that much tax and still be walking the face of this planet (as these three corporations assuredly are), and it’s tempting to think these numbers must reflect some quirk in Capital IQ’s methodology. The study pulled cash tax figures from SEC filings, divided them by companies’ pretax income (excluding extraordinary items), and then averaged the results over four years.

Be that as it may, the numbers are certainly revealing. As you might expect, most companies pay less than the 35 percent statutory maximum rate. Still, the average tax hit is painful enough, at 30 percent.

Of course, some businesses pay quite a bit less. Energy firm Range Resources, for example, paid just 0.4 percent. Utilities and energy companies crowd the ranks of the lower-rate payers. These organizations can benefit from a range of tax breaks, such as credits for enhanced oil recovery, favorable treatment for oil drilling costs, and incentives to develop renewable resources.

Other tax breaks that contributed to low overall rates include: favorable treatment of employee stock options, refunds for Hurricane Katrina relief, net operating loss carry-forwards, research credits, and deferred taxes on foreign earnings. ###