President Barack Obama is moving to close tax loopholes for American companies overseas.
Mr Obama has proposed outlawing offshore tax-avoidance techniques.
The move, which has sparked concern amoung the business community, could hit US corporations with overseas divisions.
The proposals would axe some tax deductions for firms that earn profits in countries with low tax rates.
Currently, US firms are allowed to defer paying taxes on profits earned overseas if they put those profits back into their foreign subsidiaries.
Mr Obama promised to change those provisions during his election campaign.
The White House estimates the plan may reap $US210 billion over the decade.
UBS AG acknowledged in February that it helped US clients conceal assets from their government. The giant Swiss bank agreed to pay a fine of $US780 million and has since identified about 320 of its American clients.