Holding companies have all been on the defensive since the June release of the Association of National Advertisers’ media-transparency report, while big ad spenders like J.P Morgan Chase, Allstate and AT&T are all reportedly auditing their media contracts. For this Digiday Confessions, we talked to an ad tech veteran who said that most agencies are involved in rebates and the low margins are not a valid reason for them to do so.

We granted anonymity in exchange for honesty. Excerpts lightly edited for clarity.

Read the full Digiday article here.