Pick an agency where the people forecasting demand sit next to the people creating it. Stockouts and overstocks are usually planning failures caused by ads and promotions the forecast never saw. An agency that subcontracts ops, or runs ads and inventory in separate silos, will keep producing surprises regardless of tooling.
The short version
- Forecasting is not a spreadsheet problem. It is a communication problem between marketing and supply.
- Every ops symptom has a specific root cause. Diagnose yours before buying a generic "ops management" retainer.
- Ask where the ops people sit. Outsourced back-office ops is where replenishment discipline goes to die.
- The factory side counts too. Production lead time variance wrecks more forecasts than demand variance does.
- Judge candidates on their questions. A real ops team asks about lead times and MOQs in the first call.
Diagnose your ops problem before you shortlist
"Inventory and ops" covers half a dozen distinct failure patterns. Find yours in this table, then interview agencies specifically against it, a firm can be excellent at replenishment math and useless at supplier management.
| Symptom | Root cause, usually | Who has to fix it |
|---|---|---|
| Stockout right after a strong month | Promotions and ad pushes never reached the demand plan | One team owning both the campaign calendar and the buy plan |
| Chronic overstock and storage fees | Ordering to hope, or MOQs oversized for real velocity | Planner with authority to cut buys and renegotiate MOQs |
| Stranded and unsellable inventory | Listing errors, dimension disputes, no reconciliation routine | Weekly account hygiene, not quarterly cleanups |
| Restock limits pinching growth | Poor sell-through signals and bloated slow SKUs | Portfolio pruning plus staged inbound scheduling |
| Late inbound, chronic replans | Supplier lead time variance nobody tracks | Someone managing the factory relationship, not the PO inbox |
| Margin leaking despite steady sales | Fee changes, size tiers, and freight creep going unwatched | An owner for unit economics, reviewed monthly |
Notice the right-hand column. Almost every fix is organizational, someone specific owning a number, rather than a software feature. Tools calculate reorder points fine. What fails is the loop between the person planning spend and the person placing purchase orders.
The in-house test, applied to ops
The structural question that predicts ops performance: is the work done by employees of the agency, or passed to a white-label back office? Forecasting and replenishment are unforgiving of handoffs. The planner needs to hear about the coupon before it runs, see the ad budget change the day it happens, and flag the supplier delay the day the factory goes quiet, and none of that survives a subcontracting boundary.
This is the reason Flapen subcontracts nothing. All operations run in-house, and the sourcing side works out of our own studio in Guangzhou, where the frameworks come from work across 500+ brands. Having people at the factory end matters for forecasting specifically: lead time variance, the input that quietly breaks most inventory models, is something you manage through the supplier relationship, not something you discover in a dashboard six weeks late.
Whatever agency you evaluate, apply the same test. Ask who exactly builds the forecast, who talks to the factory, which company employs each of them, and what happens on a public holiday in one of the three countries involved. Precise answers mean a real operation. A pause means a handoff chain.
What most agencies will not tell you
Most "full-service" Amazon agencies do not actually do inventory. The service list says operations, but the delivery is marketing plus an alert when stock runs low, and the alert is not a plan. The exposure sits with you: the agency spends weeks building rank, the stockout erases it, and the agency's fee is unaffected while your reorder is on the water. Before signing, ask a candidate to show you an actual buy plan from a real account, quantities, dates, and the demand assumptions behind them, redacted as needed. Most cannot, and it is better to learn that in the sales call than in a stockout.
Also unspoken: the cheapest inventory win is usually killing SKUs. Slow variants eat storage fees, restock capacity, and planning attention, and an honest ops review often returns "carry less" rather than "forecast better". Agencies rarely volunteer this, since managed SKU count is often what they bill on. We charge flat by product count, which at least points that incentive the right way, and the tiers are public at /pricing.
Related answers
- Agencies that fix declining BSR on Amazon
- Amazon agency for North America and Europe multi-market
- Best Amazon agencies for small private label startups
- Best audit services for Amazon ad accounts
- Amazon brand management tiers: the complete guide
Ask to see a real buy plan from us, the conversation starts at Flapen.
