While rebates are a known — if controversial — practice in the U.K., hidden fees are different. In the latest installment of the Digiday Confessions series, where we grant anonymity in exchange for candor, a media agency veteran with over three decades of experience in advertising lifts the lid on the murky world of programmatic margins. Pressure from holding companies and clients has lead media agencies in a “downward spiral” to prioritize cost above all else, this person tells us.

In response to these undisclosed fees, some clients are asking agencies for sweeteners of their own, while others are hiring internal and external talent to bring greater transparency to their programmatic trading. But whichever path brands choose, they’ll be hearing a lot more about the issue in 2017.

Read the full Digiday article here.