Costco Stock: December Sales, Expansion & Risks Q4

Costco’s momentum meets competing headwinds

Costco Wholesale (NASDAQ: COST) closed a week marked by clear, tangible drivers: a stronger-than-expected December sales cadence that helped lift the share price, accelerated real-estate activity and a short-term membership push — counterbalanced by notable insider stock sales and a labor authorization that could disrupt operations. The balance of these factors is shaping investor sentiment for the remainder of Q1 2026.

December sales and the immediate stock reaction

Sales surprise with measurable impact

For the five-week period ending Jan. 4, Costco reported net revenues of approximately $29.9 billion, an 8.5% year-over-year increase, with comparable sales up roughly 7.0%. That strong holiday performance catalyzed a multi-day rally: shares traded above $940 on Jan. 12 and outpaced many peers in the discount/membership retail space.

Market context and positioning

The December beat reinforced the defensive appeal of Costco’s membership model — reliable recurring revenue and strong inventory turns — at a time when many retailers face uneven demand. Despite the recent gains, COST remains below its 52-week high, signaling that investors are rewarding near-term results while still pricing in uncertainty.

Growth initiatives: warehouses and member acquisition

Faster-than-expected openings

Costco is accelerating physical expansion in key regions. A new 161,251-square-foot warehouse in Forney, Texas is now slated to open in March 2026 — three months earlier than planned — and the company expects several additional openings by April. These openings can increase local membership penetration and lift unit sales in nearby clubs.

Targeted membership promotion

To attract lapsed or new shoppers, Costco rolled out a limited-time incentive for Gold Star memberships (with auto-renewal), providing a modest digital shop card for eligible signups. Promotions like this are low-cost ways to accelerate member counts and incumbent loyalty, supporting long-term membership revenue.

Insider sales: signaling or routine rebalancing?

Recent filings

Several high-level insiders disclosed share sales in the last weeks: an outgoing Senior EVP sold roughly 1,500 shares near the mid-$900s, another executive sold about $2.3 million of stock in December at lower prices and additional filings indicate planned small disposals. These transactions have drawn investor attention because large executive sales can be interpreted as either personal liquidity moves or subtle signals about near-term prospects.

How investors typically view such sales

Insider sales do not necessarily reflect company fundamentals, especially when executives approach retirement, rebalance portfolios, or meet tax/liquidity needs. Still, clustered sales during a period of price volatility can heighten short-term sentiment risk and warrant monitoring alongside operating metrics.

Labor risk: Teamsters strike authorization

Scope and immediacy

The Teamsters, representing a meaningful subset of U.S. workers, authorized a strike should negotiations not conclude by the end of January. While the union covers a minority of total employees, successful strikes could affect fulfillment, in-club service levels and localized inventory flows—any of which would have operational consequences for revenue and customer experience.

Potential investor implications

Markets tend to react to tangible operational disruptions more than to bargaining postures. If negotiations remain orderly and a deal is reached, the authorization may pass with little impact; if not, even limited walkouts could create headline risk that temporarily pressures the stock despite solid underlying sales growth.

Conclusion

Recent, concrete developments paint a nuanced picture for COST: strong holiday sales and a step-up in expansion and member acquisition are clear positives supporting revenue and long-term membership value. Counterweights include insider share disposals and a labor authorization that introduce execution and sentiment risk. For investors, the near-term focus is on whether operational momentum — new club productivity and continued comp growth — can remain uninterrupted while management navigates labor talks and routine insider transactions.