How to prevent overselling across Amazon and eBay (UK, 2026)

Stop allocating stock per channel. In MaxInvent this is the default — the product has one stock number and every channel sees it. If you're on Linnworks / Veeqo, switch to 'Total stock' mode rather than 'Allocated'. Split allocation is the 1990s approach and guarantees stranded stock.

• Stranded stock ('10 on eBay but Amazon is out') is a direct revenue loss.
• Single-pool means the 'first order to land' wins — which is almost always fine if your sync is fast.

A buffer is stock held back from the channel. If you physically have 100 units and set a 10% buffer, Amazon and eBay see 90. This absorbs the race-condition window during concurrent sales. Start with 10% for fast-movers, 5% for slow-movers, 15-20% for anything selling 20+ units/day.

• Fast-movers (5+ sales/day per channel) need larger buffers because the race window has more collisions.
• Slow-movers (under 1 sale/day) can run at 0% buffer safely — collisions are statistically unlikely.
• MaxInvent recalculates recommended buffers nightly based on the previous 14 days of velocity.

Stock sync every 15 minutes is the baseline. Every hour is not acceptable on Amazon UK — the race window is too wide. MaxInvent runs stock sync every 15 min by default and pushes deltas immediately on dispatch (event-driven, not poll-only).

• Poll-only (periodic push regardless of change) is safer than event-only (push only on change) because it recovers from missed events.
• Best practice is hybrid: event-driven immediate push + 15-min poll as a backstop.

A 'burst sale' is when a SKU sells faster than your sync cadence. Configure MaxInvent to detect this (e.g. 2 sales in under 60 seconds) and auto-pause the SKU on non-primary channels for 60 seconds while stock propagates. The 60-second pause is invisible to 99% of buyers.

• Pick a 'primary channel' per SKU — usually whichever has the highest margin or volume.
• On burst, the primary keeps selling; secondaries pause briefly until sync catches up.

Even with buffers and fast sync, the occasional oversell is inevitable. Document a clear recovery flow: detect (MaxInvent flags over-allocated orders automatically), contact buyer within 2 hours with sincere apology + full refund + £5 voucher, and on Amazon, proactively message Seller Support before the buyer does to minimise A-to-Z risk.

• A proactive refund typically prevents A-to-Z claims on Amazon.
• On eBay, a voucher and quick response usually saves the feedback.
• Track oversells as a KPI. If you're above 0.3% of orders, your buffers are too low or sync cadence too slow.

MaxInvent's Oversell Risk dashboard shows: total oversells in the last 7 days, top offending SKUs, suggested buffer adjustments, and estimated revenue protected by your buffer strategy. Review it every Monday morning. If specific SKUs keep oversell-ing, raise their individual buffer rather than raising the global one.