CNH Global, the maker of Case and New Holland tractors, has joined the list of companies reporting a hit from President Barack Obama's controversial healthcare reforms, saying they will cost it $20m in earnings.

The US-based group, which is controlled by Italian car giant Fiat, said it would take the charge in its results for the first quarter of 2010.

The hit reflects changes in President Obama's hard-fought healthcare overhaul which remove tax benefits covering payments made to cover retiree workers' prescription drugs.

Controversial measure

The move adds CNH to a list of companies including Boeing, Caterpillar and Deere & Co which have unveiled charges for similar reasons, and often much larger in scope, because of the healthcare bill, which has been branded by Republican representative Dave Camp "the single largest tax increase in American history".

However, the White House has defended the change to prescription drug benefits as ironing out an anomaly, given that they attracted support in the form of government subsidies as well as the tax benefit.

"[Companies] get the subsidy, that's not counted as income," White House spokesman Robert Gibbs said.

"Then they get to write off the spending. Our bill simply closes the loophole."