What is in the stack
Under Vendor Central, Amazon's terms include co op, which is a percentage of purchases the vendor funds toward Amazon marketing, plus marketing development funds, damage and freight allowances, and volume or growth rebates. Names and mechanics vary by market and category, and the terms are renegotiated every year in the annual vendor negotiation.
What it costs
Across the allowance stack, the figures brands cite run from 9 to 22 percent of invoiced revenue in 1P. Annual trade allowances alone are commonly cited at 12 to 18 percent. These costs usually live in a trade or marketing budget, not in the Amazon channel P&L, which is how a channel with a 45 percent reported gross margin can be a low single digit net contribution once fully loaded.
How to treat it in the JBP
Co op is a negotiating lever and a measurement problem. Ask what each point buys: which placements, which events, what incrementality. Tie the commitment to outcomes in the JBP, and track it against Net PPM so the funding does not push an ASIN under Amazon's margin target.