NEW YORK (TheStreet) -- A report released by Americans for Tax Fairness is taking aim at Walmart (WMT) -- revealing that the retail giant has established undisclosed subsidiaries in overseas tax havens. 

The report found that Walmart has established at least 78 subsidiaries and branches in 15 tax havens -- and that the company has never listed any of these in its annual 10-K filing with the SEC.

The study, researched by the United Food and Commercial Workers International Union, found that Walmart used these subsidiaries to pursue "international tax avoidance strategies."

Walmart spokesperson Randy Hargrove said the company disclosed its significant subsidiaries in its 10-K, which he said is compliant with SEC regulations.

He added, "This is the same union-supported group that regularly issues similar, flawed reports on Walmart to promote their agenda rather than the facts. This latest report includes incomplete, erroneous information designed to mislead readers."

Hargrove noted that Walmart paid $6.2 billion in U.S. federal corporate income tax last year. He said that equates to nearly 2% of all corporate income tax collected by the U.S. Treasury in 2014.

"Walmart has processes in place to comply with applicable SEC and IRS rules, as well as the tax laws of each country where we operate, and we maintain transparency with the IRS via real-time disclosure of our business transactions and corporate structure," he said. 

Based on its findings, the study's researchers ask that the SEC pursues more information from Walmart, and the IRS audits Walmart's use of subsidiaries in tax havens.

The report also recommends that parliaments and tax authorities in the U.K., Mexico, Japan and elsewhere investigate the company's business practices within their borders, and that the European Commission examines Luxembourg and Walmart's presence there.

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