Dozens of US exporters including GE and Boeing are squaring off against Walmart and other retailers as a radical Republican plan to tax imports divides the giants of corporate America. The rift in the business community threatens President Donald Trump’s pledge to overhaul the tax code for the first time in 30 years by undermining a blueprint that House Republicans are drafting for the White House. The Financial Times has learnt that GE, Boeing, Dow Chemical and dozens of other manufacturers are in advanced talks over forming a coalition to lobby in favour of the import tax, just as Walmart and other big importers, including the billionaire Koch brothers, rally against it. Walmart sent its top tax executives to meetings on Capitol Hill this week to warn officials that the proposal would have a dramatic impact on its business, potentially forcing the retailer to raise prices for shoppers, according to two congressional aides. The “border adjustment” tax regime, which would penalise imports and exempt exports, is central to the plans of House Republicans initiating tax legislation. But visceral divisions over the idea do not bode well for its prospects.