After a 7‑Year Delay, Costco China Finally Launches Black Diamond Membership

Big reveal: higher rebate, new tier

Costco (开市客) has signalled a strategic upgrade in China: it has been reported that the company’s Little Red Book account announced a forthcoming "black diamond" (黑钻会员) — the local analogue of Costco’s US Executive Membership — with a headline-grabbing 3% cashback, reportedly the highest rebate in Costco’s global network to date. In North America, Executive members typically receive 2% back (capped at US$1,250), so a 3% offer would be a notable premium aimed squarely at China’s value‑sensitive shoppers.

Why now? Seven years of data and supplier work

When Costco opened its first mainland China warehouse in 2019 it only offered a single 299‑yuan tier. The subsequent seven years were quietly busy: Costco opened seven stores across six cities, built local supply chains, accumulated millions of membership transactions and — it has been reported — even convened its first domestic supplier conference in 2025 to push Chinese-made goods into its global sourcing matrix. That slow rollout was not just caution. It was data gathering: which SKUs drive repeat purchase, where delivery fails, and what high‑value members actually want.

Strategy and stakes: differentiation or duplication?

Tiered membership lets Costco tilt scarce premium services — faster delivery, dedicated support, exclusive time slots — toward the highest‑value customers. Competitor Sam’s Club (山姆) already runs a similar playbook in China with rebates, fee waivers and shipping perks, so can Costco design sufficiently differentiated benefits to avoid a commoditised race to the bottom? Costco’s own international results suggest high‑tier members punch well above their numbers: according to its 2025 reporting, premium members account for a disproportionately large share of sales and ARPU, a dynamic Costco hopes to replicate in China.

Local frictions remain the test

Execution will matter. Chinese members have complained about sparse online SKUs, high delivery thresholds and slow refunds — real weaknesses in a market that prizes seamless e‑commerce. Will a 3% rebate and tailored privileges overcome those frictions and accelerate store expansion, or will they merely re‑segment existing shoppers? The black diamond launch signals a shift from model validation to “precision operations.” The answer will determine whether Costco’s China story becomes an expansion play or a niche premium strategy.