New research has revealed that 73% or 366 companies on the Fortune 500 list, including brands as big as Nike, Apple and Citigroup, used tax havens to avoid US taxes in 2016.

A new report, published on Tuesday (17 October) by the Public Interest Research Group (PIRG) Education Fund and the Institute on Taxation and Economic Policy in the US, suggests that nearly three in four Fortune 500 companies maintained subsidiaries in offshore tax havens last year.

Fortune 500 companies' offshore cash hoard now totals $2.6trn (£1.97trn), a sum on which these companies are avoiding up to $752bn in US taxes, the report adds.

These 366 companies collectively maintain at least 9,755 tax haven subsidiaries. Four companies – Apple, Pfizer, Microsoft and General Electric – account for 25% of Fortune 500 companies' offshore cash.

Overall, 30 Fortune 500 companies account for 68%, or $1.76trn, of the noted offshore profits.

Loopholes in the US tax code, such as one that allows corporations to indefinitely defer taxes on profits booked offshore, gives companies an incentive to artificially shift US profits to countries with zero- or low tax rates to avoid taxes.

Michelle Surka, programme director at PIRG Education Fund, said with the US Congress looking to pass tax cuts that would cost upwards of $5tr, it's all the more unacceptable to leave open absurd loopholes and gimmicks for the biggest multinational corporations.

"Tax reform should inject some common sense into our tax code, and it shouldn't balloon the US deficit. Closing tax haven loopholes would both eliminate some of the most ridiculous tax gaming and help balance our budget," she added.

Richard Phillips, a senior policy analyst at the Institute on Taxation and Economic Policy, commented: "Real tax reform would fix the deferral loophole, not reward companies for using the loophole to avoid taxes year after year.

"Lawmakers shouldn't be discussing how to sweeten the pot and give corporations a huge tax break that amounts to a huge financial reward for engaging in bad corporate behaviour."