US corporate giants such as Apple, Walmart and General Electric have stashed $1.4tn (£980bn) in tax havens, despite receiving trillions of dollars in taxpayer support, according to a report by anti-poverty charity Oxfam...The charity's analysis of the financial affairs of the 50 biggest US corporations comes amid intense scrutiny of tax havens following the leak of the Panama Papers...Oxfam estimates that tax avoidance by US corporations costs the world's largest economy some $111bn a year, but said it was also fuelling the global wealth divide by draining $100bn from the poorest countries. "Tax dodging practised by corporations and enabled by federal policymakers contributes to dangerous inequality that is undermining our social fabric and hindering economic growth," the report said...The charity called on the US government to pass the Stop Tax Haven Abuse Act, including a requirement for firms to report their tax contribution on a country-by-country basis...