Companies across all industries and sectors would pay an averageeffective tax rate of 9 percent next year under the Republicantax-overhaul bill, a Penn Wharton Budget Model study said onTuesday.

By 2027, that average effective rate would double to 18percent—because of some corporate tax breaks that would move offthe books, according to researchers for the economic policy centerat the University of Pennsylvania's Wharton School of Business.

The bill would cut the corporate tax rate to 21 percent—downfrom 35 percent currently—but the study examined how its variouschanges would affect the actual taxes companies pay on their pretaxincome. Because of differing deductions and tax strategies, acompany's effective tax rate can vary greatly from the “statutory”rate. Currently, U.S. companies pay an average effective rate of 21percent, according to the Penn Wharton report.