More grist for the anticorporate mill.

Thirty major U.S. public companies, including San Francisco's PG&E Corp. and Wells Fargo & Co., paid no federal taxes over the past three years, according to a report released Thursday. A number of them, notably Wells Fargo, also benefited greatly from various tax subsidies.

A number of other Bay Area companies appear not to have paid their fair share - i.e, less than half the nominal 35 percent corporate tax rate - including Hewlett-Packard, Yahoo and Levi-Strauss.

The report, compiled by an advocacy group, Citizens for Tax Justice and the nonpartisan Institute on Taxation and Economic Policy, examined corporate financial statements from 280 companies on the Fortune 500 list, all of whom were profitable during the 2008-10 period.

"These 280 corporations received a total of nearly $223 billion in tax subsidies," said Robert McIntyre, director at Citizens for Tax Justice and the report's lead author. "This is wasted money that could have gone to protect Medicare, create jobs and cut the deficit."

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But other companies seem to be paying their fair share and more. And some companies have questioned the report's accuracy and say the tax breaks have been used for legitimate and positive purposes.

Fourth on the list of non-payers, for example, is PG&E, which according to the study paid no federal income tax on combined profit of $4.85 billion, while netting more than $1 billion in tax breaks over the three-year period. "This goes back to measures to stimulate the economy, allowing for accelerated depreciation to encourage investment," said Brian Herzog, a spokesman for PG&E. "We used the money to make large-scale capital investments in infrastructure, as Congress intended.

"And we're able to use those tax savings instead of raising money in the capital markets, the costs of which would generally be passed along to consumers," he said.

Accelerated depreciation was one of the chief ways companies were able to pay so little in federal taxes, along with stock options, tax shelters and industry-specific tax breaks, according to the report.

Context: Topping the tax savings list was Wells Fargo, which received $18 billion in tax savings over three years while making $48 billion in profit.

Wells Fargo spokesman, Ancel Martinez, said the report "takes data out of context to advance an agenda."

"Over the past 10 years, Wells Fargo has paid more than $30 billion in income taxes to federal and state authorities and billions more in other taxes, and it fulfills all tax obligations. The years cited by the study included significant losses from its (2008) acquisition of Wachovia, which when realized reduced Wells Fargo's taxable income.

"Based on results for the first three quarters 2011, Wells Fargo expects to pay significant income taxes for 2011," said Martinez.

HP, which paid just 3.7 percent of its taxable profit over the three-year period, according to the report, declined to comment. Yahoo (8.7 percent) and Levi Strauss (10.2 percent) did not respond to requests for comment Thursday afternoon.

Paying up: Some tax analysts say there can often be a difference between corporate financial statements, which formed the basis of the report, and actual tax returns, and that major corporations often count state, local and, where applicable, foreign taxes, amongst others, into their "effective" tax rate.

According to a recent analysis of IRS data by the nonpartisan Tax Foundation, the effective corporate tax rate from 2003 to 2008 stood at 26 percent of pretax profit. In 2008, as in most years, it said, "taxes paid exceeded after-tax profits."

As itemized in the CTJ/ITEP report, Clorox, headquartered in Oakland, paid 26 percent over the past three years.

Other Bay Area companies joining Clorox in the fairer share list include Chevron and Safeway (24 percent); Visa (28 percent); Oracle (29 percent); Apple, Intel and Charles Schwab (31 percent); Ross Stores (34 percent); and Gap (40 percent).

The economic sector paying the most in total taxes (average, 30 percent) was wholesale and retail - with the exception of Amazon.com, whose business model has long rested on not paying state sales taxes. The online behemoth paid a rate of only 7.9 percent on its $1.8 billion in profit from 2008 to 2010.