Three influential policy groups that together receive almost $20m in donations a year refuse to reveal their key donors, including those whose commercial interests may overlap with their public advocacy campaigns. The progressive Australia Institute, the right-leaning Centre for Independent Studies and the conservative Institute of Public Affairs argue they cannot reveal their donors without exposing them to attack from political opponents.

Slack. Good on Grattan, CEDA and Per Capita for being more honest about their funding.

Reported by Henry Belot for _The Guardian _