The Organization for Economic Co-operation and Development (OECD) is calling for more global co-operation on corporate tax regimes to ensure that large companies pay their fair share.

The Paris-based OECD said Tuesday that a study commissioned by the G20 found that some multinationals use strategies that allow them to pay as little as 5% in corporate taxes when smaller businesses are paying up to 30%. OECD research also shows that some small jurisdictions act as conduits, receiving disproportionately large amounts of foreign direct investment compared to large industrialized countries and investing disproportionately large amounts in major developed and emerging economies.

The group notes that many of the existing rules, which protect multinational corporations from paying double taxation, too often allow them to pay no taxes at all. It stresses that these rules do not properly reflect today’s economic integration across borders, the value of intellectual property or new communications technologies. And, it says, these gaps, which enable multinationals to eliminate or reduce their taxation on income, give them an unfair competitive advantage over smaller businesses. “They hurt investment, growth and employment and can leave average citizens footing a larger chunk of the tax bill,” it adds.

The report also says that the practices multinational enterprises use to reduce their tax liabilities have become more aggressive over the past decade. “Some, based in high-tax regimes, create numerous off-shore subsidiaries or shell-companies, each time taking advantage of the tax breaks allowed in that jurisdiction. They also claim expenses and losses in high-tax countries and declare profits in jurisdictions with a low or no tax rate,” it says.

The OECD stresses that its report does not suggest optimal tax rates, as each government decides its own. But, in the coming months, it will draw up an action plan to further quantify the corporate taxes lost and provide concrete timelines and methodologies for solutions to reinforce the integrity of the global tax system.

“These strategies, though technically legal, erode the tax base of many countries and threaten the stability of the international tax system,” said OECD secretary-general, Angel GurrĂ­a. “As governments and their citizens are struggling to make ends meet, it is critical that all tax payers – private and corporate – pay their fair amount of taxes and trust the international tax system is transparent. This report is an important step towards ensuring that global tax rules are equitable, and responds to the call that the G-20 has made for the OECD to help provide solutions to the global economic crisis.”