Platform listings grow by hundreds of thousands weekly. Sell-through rates drop. This isn't market growth - it's oversupply destroying the economics.

The industry produces 92 million tonnes of textile waste annually, heading to 134 million by 2030. The global resale market will hit $367 billion by 2029. Even optimistically, resale captures 20-25% of production. The arithmetic fails.

For resellers, oversupply manifests as crisis. Managed warehouses fill with aging stock. Capital ties up while storage costs accumulate. Peer-to-peer platforms drown in listings - Vinted has hit over 100 million users with millions of active listings. When buyers can't find what they want through the noise, sell-through collapses.

The sneaker market proved what happens next. Nike flooded supply. Resale premiums that hit 100%+ collapsed to 10-25%. When retail had stock, the secondary market value evaporated. Nike cut production 35% to restore exclusivity, but the damage was done. Platform closures followed. Resellers pivoted to volume plays on margins too thin to sustain.

Fashion apparel is tracking the same path. UK textile donation values dropped 57.5% in a decade. Some items arrive new-with-tags, going to recyclers at 35p per kilo. The processing costs exceed value. The operational burden defeats the margin.

Yale research from December 2025 confirms what we've documented through operator interviews - secondary markets may encourage unsustainable purchasing rather than solve overconsumption. Fast fashion's model requires consumers dispose quickly to buy again. Resale facilitates that disposal, making it feel virtuous while enabling the cycle.

The quality collapse compounds it. Platforms prefer pristine inventory - easier to photograph, describe, price. Consumers avoid repairs knowing resale values plummet. Market signals say "replace, don't repair." Items with years of life get discarded because reconditioning would "damage resale value."

What You Could Do This Week

☐ Calculate your intake-to-sell-through ratio by category - If items sit unsold past 90 days, you're accumulating dead weight. Use this data to stop accepting categories that don't move.

☐ Audit true carrying costs per unsold item - Warehouse space, handling touches, markdown losses, eventual liquidation. This number determines which intake you can afford.

☐ Implement velocity-based intake criteria - Accept only items with demonstrated 30%+ sell-through rates in your historical data. Volume without velocity kills margins.

Resellers surviving the next wave won't have the most inventory necessarily - they'll have the highest sell-through on items that actually sell at margins that work.