> Dealers have inventories - they purchase items from the suppliers and resell them - if they misjudge demand, they're left off with useless goods.

Everything is negotiable. If a retailer has more power than a supplier, then the retailer can demand a guaranteed sale clause in the contract, requiring the supplier to take back unsold goods and refund them.

https://www.comcapfactoring.com/blog/walmart-vendor-financin...

https://factor-this.com/walmart-supplier-financing/