Iowa is among six states considering legislation to prevent tax-avoidance strategies practiced by large corporations, according to a report from the Center on Budget and Policy Priorities, a nonprofit, nonpartisan research institute.

“Combined reporting” has been approved in 18 states, and is being recommended for passage by governors in Iowa, Massachusetts, Michigan, New York, North Carolina and Pennsylvania. The tax reform measure is in response to a growing number of large multistate corporations creating “tax haven” subsidiaries to hide profits and avoid paying corporate income taxes. Under combined reporting, the state taxes a share of the company’s combined nationwide income. The amount that is taxed is based on how much of the corporation’s total activity takes place in that state.

In his budget address in January, Gov. Chet Culver said requiring combined reporting would save taxpayers millions by closing corporate tax loopholes, and also allow the state to offer up to $25 million in immediate commercial property tax relief.

The Iowa Taxpayers Association opposes combined reporting, saying it could cost Iowa companies “hundreds of thousands, if not millions” of dollars in reporting expenses and make the state less attractive to businesses.