The lobbying scandal rocking Washington has centred so far on corrupt relationships between lobbyists and legislators. But the issue is also giving new impetus to governance activists, who are increasingly demanding that big business do a better job of disclosing - and justifying - political donations.

A group of pension funds led by William Thompson, the New York City comptroller, is stepping up demands that six companies, including Wal-Mart and Chevron, disclose all direct and indirect political contributions to lawmakers and political parties.