A new study says corporations that make deposits in foreign banks cost Arizona $286 million in tax revenue last year. The report is being released Thursday by the Arizona Public Interest Research Group. 

Spokesman Dan Smith says Fortune 500 companies that use overseas tax shelters are hurting the state.

“We found if the average taxpayer was going to make up for the lost state and federal tax revenue to tax havens, the average Arizona taxpayer would have to pay $927 a year," Smith said.

Smith says U.S. firms are not breaking any laws by using foreign banks, but he says Congress needs to approve laws banning the practice. 

He says Congress has moved to remove some tax loopholes, but corporations are still finding ways to skirt the new regulations.