Costco beat its Q3 FY2026 earnings per share estimate by a single cent, then fell 4.7% the next day, exceeding the expected move that options had priced in. That outcome illustrates the core challenge in premium selling around earnings: even a technical beat does not guarantee the stock stays inside the implied range.
- Costco reported Q3 FY2026 EPS of $4.93, beating the $4.92 consensus estimate. Net sales rose 11.6% to $69.15 billion.
- The stock fell approximately 4.7% the day after the announcement, exceeding the roughly 3.6% expected move priced into options before the report.
- Premium sellers positioned with short straddles at or near the money took losses on the put side. Defined-risk iron condors with well-placed strikes fared better.
- IV crush occurred as expected after the announcement resolved the earnings uncertainty.
- Membership renewal held at 92.2% in the U.S. and Canada, signaling continued strength in the company’s recurring revenue base.
What Costco Actually Reported
Costco released Q3 FY2026 results after the market close on May 28, 2026. The headline numbers:
- Net sales: $69.15 billion, up 11.6% year-over-year
- EPS (diluted): $4.93 vs. $4.92 consensus estimate (beat by one cent)
- Comparable sales: +9.8% company-wide, +9.4% in the U.S., +10.7% in Canada, +11.2% in other international markets
- Digitally-enabled comparable sales: +21.5% for the 12-week quarter
- U.S. and Canada membership renewal rate: 92.2%, up 10 basis points sequentially from the prior quarter
- Worldwide renewal rate: 89.7%, unchanged sequentially
On the surface, these numbers look strong. Double-digit revenue growth, accelerating comparable sales, and e-commerce running at 21.5% growth all point to a business in good shape. The EPS beat was narrow but real.
For context on the retail backdrop, Walmart and Target both disappointed on guidance in the weeks before this report. Investors were watching whether Costco’s membership-driven model would insulate it from similar pressures. You can read more about how those results played out in the WMT and TGT post-earnings options recap.
The Actual Stock Move: 4.7% Down on a Beat
Before the Q3 report, options markets priced in an expected move of approximately 3.6% in either direction for the May 29 weekly expiration. This figure comes from the at-the-money straddle price, which represents the market’s collective estimate of the post-earnings range. The TRD pre-earnings article (Costco Q3 2026 Earnings: Options Expected Move and Pre-Earnings IV Setup) covered the specific setup figures ahead of the report.
Costco closed near $1,003 on May 28 before reporting after hours. By the following day’s close, the stock had declined approximately 4.7%, settling near $957.
That 4.7% move exceeded the expected move on the downside. Historical data shows COST exceeded its implied move in three of the prior eight earnings announcements, with notable instances being a 6.6% drop in March 2025 and a 4.9% drop in September 2025. This quarter joined that group.
Why did the stock drop on a beat? Several factors combined:
- A minimal beat leaves little room for surprise: One cent per share above consensus means the beat was largely anticipated. There was no meaningful positive surprise to unlock buying pressure beyond what was already priced in.
- Retail sector sentiment: With Walmart and Target having recently disappointed on guidance, investors were primed for caution in the consumer sector. Any softness in COST’s numbers read more negatively in that context.
- Valuation context: COST trades at a significant premium to the S&P 500. At over $1,000 per share with a correspondingly elevated P/E ratio, the stock has less room to absorb even slight revenue benchmark misses before the premium compresses.
How Options Traders Were Positioned
The following examples are illustrative only and represent hypothetical trades, not actual trade recommendations. They use approximate prices based on available data for the May 29 expiration.
Short Straddle at the Money
A hypothetical short straddle with both legs struck at $1,000 would have collected approximately $36 in total premium, reflecting the 3.6% expected move. After the 4.7% decline, the $1,000 put would have moved deep into the money. A roughly $47 decline against $36 collected yields a hypothetical net loss of about $11 per share ($1,100 per contract) before commissions, assuming no early management.
This is the risk in undefined-risk straddles on earnings: when the stock moves beyond the expected range, losses compound with no cap.
Iron Condor (Defined Risk)
A hypothetical iron condor with the put spread at $960/$940 (short the $960 put, long the $940 put) and the call spread at $1,040/$1,060 (short the $1,040 call, long the $1,060 call) would have collected approximately $7 in net premium, depending on bid-ask conditions at entry.
With COST settling near $957, the $960 short put is slightly in the money. The put spread faces a maximum loss of $20 (the spread width) minus the $7 credit, or approximately $13 per spread ($1,300 per iron condor). The call spread expires worthless, keeping its credit.
Had the put spread been structured wider, say $940/$920 for a similar credit, the $957 settlement would have landed outside the short strike, resulting in a profitable trade. Strike selection is particularly consequential for lower-beta names like COST where the margin between inside and outside the expected range is often just one to two percentage points.
Long Straddle
A hypothetical long straddle at the $1,000 strike would have cost approximately $36 to enter. The 4.7% decline delivers approximately $47 in intrinsic value on the put leg. After paying the $36 premium, the hypothetical gross profit is approximately $11 per share ($1,100 per contract) before commissions, assuming a close at or near expiration on May 29.
Long straddle buyers benefited here because the actual move exceeded the expected range. Note that IV crush after the announcement reduces the time value component of the long position, so the full intrinsic value is only captured cleanly on settlement or if the option is held to expiration.
Strategy Comparison
| Strategy | Entry (approx.) | Outcome at -4.7% | Hypothetical P&L |
|---|---|---|---|
| Short straddle ($1,000) | +$36 credit | Put deep in the money | -$11/share (-$1,100/contract) |
| Iron condor ($960/$940 put spread, $1,040/$1,060 call spread) | +$7 credit | Put spread slightly breached | -$13/spread (-$1,300/spread) |
| Long straddle ($1,000) | -$36 debit | Put moves $47 intrinsic | +$11/share (+$1,100/contract) |
All figures are hypothetical and approximate. Actual results vary based on entry timing, execution, bid-ask spreads, and position management decisions.
IV Crush After the Announcement
Implied volatility rose through the weeks before the May 28 report, following the standard pre-earnings IV expansion pattern. After results hit, IV collapsed as the uncertainty resolved. That is standard post-earnings behavior for any liquid equity.
IV crush had different effects across strategy types this quarter. Long straddle holders saw their put gain intrinsic value from the directional move, but IV crush simultaneously reduced the time value component, partially offsetting the gain. Short premium traders saw IV crush help on the untested call spread leg (the short calls lost value quickly after earnings), but directional losses on the put side were larger for at-the-money setups.
This dynamic is one reason some traders prefer to size down on earnings plays: the interaction between directional risk and IV crush makes the outcome binary in a way that day-to-day premium selling is not.
Membership Data as a Forward Signal
Costco’s membership renewal rate is the metric that analysts and options traders focus on most closely for forward revenue visibility. Membership fees are near-pure revenue with minimal marginal cost, and renewal rates above 90% in the U.S. signal predictable future cash flow quarter after quarter.
At 92.2% renewal in the U.S. and Canada (up 10 basis points sequentially), the membership business remains healthy. The worldwide rate of 89.7% held steady. Management noted growth in new member sign-ups alongside stable renewal rates, which is the combination that drives membership fee compounding over time.
The post-earnings decline, then, was primarily a reaction to the narrow EPS beat, revenue benchmarks, and sector context rather than any deterioration in the core membership business. For traders who use COST as a recurring earnings setup each quarter, the membership metrics continue to support the thesis that COST is a lower-volatility, typically muted-move name.
Bottom Line
COST’s Q3 FY2026 beat was too narrow to generate a positive reaction, and the stock dropped 4.7%, exceeding the 3.6% expected move. Premium sellers positioned near the money took losses unless their strikes provided enough cushion below spot. Defined-risk structures limited the damage compared to undefined-risk positions. The quarter is a clean example of why the expected move is a probability range, not a ceiling, and why earnings size management matters even for historically muted names.
For traders who want to track IV crush in real time and assess P50 for each strategy before the next earnings event, tastytrade is purpose-built for probability-focused premium selling. For multi-leg spread execution with customizable analytics and global market access, Interactive Brokers supports the full range of spread structures covered here.
Frequently Asked Questions
Q: How much did Costco stock move after Q3 FY2026 earnings?
A: Costco fell approximately 4.7% the day after reporting Q3 FY2026 results on May 28, 2026, exceeding the roughly 3.6% expected move that options had priced in before the announcement.
Q: What was the expected move for COST’s Q3 2026 earnings?
A: Options markets priced in approximately a 3.6% expected move in either direction for the May 29 weekly expiration. The actual 4.7% decline fell outside this implied range, making it one of the less common cases where COST exceeded its expected move (historically around 3 of the past 8 quarters).
Q: Why did Costco stock fall if earnings beat estimates?
A: COST beat EPS by only one cent ($4.93 vs $4.92 est), providing minimal positive surprise beyond what was already priced in. Combined with the broader retail sector’s cautious post-earnings environment and Costco’s premium valuation, the market sold off despite the technical beat.
Q: What happened to implied volatility after Costco’s Q3 2026 earnings?
A: Implied volatility collapsed after the report, as is standard for earnings events. This IV crush reduced the time value of all options. For short premium traders, IV crush helped on untested legs of spread structures, but directional losses on the put side were larger for at-the-money setups.
Q: What is Costco’s membership renewal rate as of Q3 FY2026?
A: As of Q3 FY2026, Costco’s U.S. and Canada membership renewal rate was 92.2%, up 10 basis points sequentially. The worldwide rate held at 89.7%. These figures reflect the ongoing strength of the membership model as a predictable revenue base for the business.