Aflac Inc. and Chubb Corp. are among a growing number ofcompanies revealing their corporate contributions, some of whichmay go to nonprofits and trade associations spending millions ofdollars on U.S. elections without disclosing their donors.

A study out today found 45 of 88 companies providing informationabout corporate donations, up from 36 a year earlier.

The trend toward corporate disclosure runs counter to a growthin campaign spending by nonprofits that don't have to identifytheir donors. Even as Republicans on the U.S. Federal ElectionCommission and in Congress block efforts to force nonprofits toidentify their donors, some corporate contributors are voluntarilydisclosing their support.