Fifty U.S. corporate giants stashed $1.6 trillion in offshore tax havens in 2015 while receiving trillions of dollars in taxpayer support, anti-poverty charity Oxfam said Wednesday.

Companies such as Apple, Pfizer, Chevron, Goldman Sachs, Walmart and General Electric moved a sum larger than the combined economic output of Canada, South Korea, Australia, Russia and Turkey out of the reach of tax collectors.

The same firms spent huge sums lobbying the U.S. government for tax breaks, receiving an estimated $1,200 in tax deductions for every $1 spent petitioning for tax cuts.

In the report, titled Rigged Reform, Oxfam revealed that "big U.S. companies are increasing their use of tax havens and boosting their investment in political lobbying in order to push for even greater tax breaks."

The 50 largest U.S. companies used a "secretive network" of 1,751 subsidiaries in tax havens to store about $1.6 trillion offshore in 2015, according to the report.

The offshore figure was $200 billion higher than in 2014, the U.K.-based charity said.

During 2009-2015, the firms spent $2.5 billion on lobbying the U.S. government. Nearly a quarter of tax lobbying was carried out by General Electric, Verizon Communications, Comcast, AT&T and Exxon Mobil.