Arbitrage Opportunities Between Amazon and eBay: Leveraging Out-of-Stock Gaps

One of the most overlooked opportunities in online arbitrage lies in exploiting out-of-stock (OOS) cycles between Amazon and eBay. Amazon’s marketplace has conditioned millions of shoppers to expect fast shipping, competitive pricing, and near-endless availability. Yet even the world’s largest retailer runs into supply chain bottlenecks. When a high-demand product goes OOS on Amazon, it creates a temporary imbalance: consumer demand remains, but supply vanishes. Smart sellers can step into this gap by sourcing the product on eBay and reselling it on Amazon—or, in reverse, selling on eBay at prices anchored to Amazon’s usual retail level.

1. Why Out-of-Stock Arbitrage Works

At its core, arbitrage relies on price discrepancies across marketplaces. Amazon typically offers the lowest prices due to scale, but when items go OOS, the few remaining third-party sellers can raise prices sharply. Meanwhile, sellers on eBay may continue listing the same products at stable or even discounted rates, often because they operate outside Amazon’s ecosystem and don’t react as quickly to price signals.

The arbitrage window opens when:

  • Amazon is OOS → prices spike due to scarcity.

  • eBay still has supply → prices remain stable.

  • Consumer urgency remains high → buyers on Amazon pay a premium to get the product quickly.

This pattern is especially common with toys, seasonal products, supplements, collectibles, and discontinued SKUs.

2. Tools for Identifying Opportunities

While manual searching is possible, efficiency comes from specialized software:

  • SmartScout: Filters Amazon’s catalog for OOS products, low inventory signals, or suppressed Buy Boxes. It also shows estimated monthly sales velocity, ensuring that you only chase items with proven demand.

  • Keepa: Tracks Amazon price and stock history. A sharp upward spike in price coupled with OOS periods indicates reliable arbitrage potential.

  • eBay Completed Listings: Validates whether inventory is available on eBay and at what historical selling price.

By combining these tools, sellers can systematically target profitable gaps rather than relying on luck.

3. The Workflow

A structured approach makes arbitrage replicable:

  1. Scan for OOS Products on Amazon
    Use SmartScout to identify products with low inventory or missing Buy Boxes.

  2. Validate Demand and Price Elasticity
    Check Keepa charts to see whether the product historically sells out and whether prices rise significantly during those gaps.

  3. Cross-Reference on eBay
    Search by ASIN, UPC, or product title to confirm eBay sellers are listing the same item new and sealed.

  4. Run the Numbers
    Use Amazon’s fee calculator to estimate net profit. Target at least 30% margin after fees and shipping.

  5. Source from eBay
    Buy small test quantities to validate quality and turnover speed.

  6. Resell on Amazon
    List via FBM for quick testing, or FBA for higher conversion if the opportunity repeats reliably.

4. Risk and Reward

Like any arbitrage strategy, OOS flips carry risks:

  • Authenticity Complaints: Amazon has strict policies; sourcing from eBay means you may not have invoices acceptable for authenticity verification. Sticking to branded, verifiable products is essential.

  • Price Collapse: If Amazon or other sellers restock suddenly, the Buy Box price can drop back to normal, leaving you with unprofitable inventory.

  • Cash Flow Pressure: Arbitrage requires upfront cash. Inventory tied up in risky flips can hurt liquidity.

Yet the rewards can be substantial. Sellers who anticipate OOS cycles—such as during Q4 holiday shopping—can capture outsized margins. It’s not uncommon to buy a toy for $40 on eBay in November and sell it for $120 on Amazon when parents are desperate to secure a gift.

5. Strategic Approaches

There are several ways to sharpen the strategy:

  • Seasonal Stocking: Anticipate demand surges (Christmas toys, back-to-school supplies) and stock ahead of time.

  • Chronic OOS Products: Some brands consistently fail to meet Amazon demand. Track these and prepare to exploit each cycle.

  • Bundles and Variations: If a single SKU is OOS, consider creating multipacks or bundles sourced from eBay, offering a differentiated ASIN that bypasses direct competition.

  • Cross-Market Arbitrage: When Amazon is OOS and inflated, but eBay buyers anchor to Amazon’s usual price, flip your arbitrage stock on eBay instead.

6. The Bigger Picture

Amazon ↔ eBay OOS arbitrage is not about building a massive, scalable business. Instead, it functions more like a sniper strategy—sharp, quick flips targeting temporary inefficiencies. For sellers already in wholesale or private label, it can serve as a profitable side channel. For hustlers starting out, it’s a low-barrier way to understand supply chains, pricing dynamics, and marketplace psychology.

Long term, those who document recurring OOS cycles can evolve from opportunistic arbitrage into systematic inventory plays, stocking the right products at the right time, and potentially developing relationships with distributors who can supply directly rather than relying on eBay.

Conclusion

The Amazon and eBay ecosystems are vast, liquid, and imperfect. Out-of-stock arbitrage thrives in the cracks between them, where consumer demand collides with temporary scarcity. Using tools like SmartScout and Keepa to spot opportunities, and sourcing strategically from eBay, sellers can capture meaningful profits. While it carries risks and requires discipline in cash flow and compliance, for those who master the workflow, it represents one of the sharpest edges in the ever-competitive world of online arbitrage.

Amazon Seller, EbayFrancesca Tabor