How Will Costco Wholesale Stock React To Its Upcoming Earnings?
Costco Wholesale (NASDAQ:COST) is set to report its earnings on Thursday, May 28, 2026. The company has $445 Bil in current market capitalization. Revenue over the last twelve months was $286 Bil, and it was operationally profitable with $11 Bil in operating profits and net income of $8.5 Bil. While the post-earnings stock reaction will depend on how the results and outlook stack up against investor expectations, a detailed look at historical results can aid you if you are an event-driven trader.
Here is how: either understand the historical odds and position yourself prior to the earnings announcement, or look at the correlation between immediate and medium-term returns post earnings and enter a trade one day after the announcement.
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Costco Wholesale’s Historical Odds Of Positive Post-Earnings Return
Some observations on one-day (1D) post-earnings returns:
- There are 20 earnings data points recorded over the last five years, with 11 positive and 9 negative one-day (1D) returns observed. In summary, positive 1D returns were seen about 55% of the time.
- However, this percentage decreases to 45% if we consider data for the last 3 years instead of 5.
- Median of the 11 positive returns = 1.9%, and median of the 9 negative returns = -2.4%
Additional data for observed 5-Day (5D) and 21-Day (21D) returns post earnings are summarized along with the statistics in the table below.
| Forward Returns | |||
|---|---|---|---|
| Earnings Date | 1D | 5D | 21D |
| 3/5/2026 | 1.6% | 2.1% | 3.7% |
| 12/11/2025 | -0.0% | -3.0% | 6.5% |
| 9/25/2025 | -2.9% | -2.8% | -1.2% |
| 5/29/2025 | 3.1% | 0.2% | -1.9% |
| 3/6/2025 | -6.1% | -13.2% | -10.7% |
| 12/12/2024 | 0.1% | -3.4% | -6.6% |
| 9/26/2024 | -1.8% | -2.9% | -1.1% |
| 5/30/2024 | -0.7% | 3.3% | 3.7% |
| 3/7/2024 | -7.6% | -6.8% | -9.4% |
| 12/14/2023 | 4.4% | 5.5% | 10.9% |
| 9/26/2023 | 1.9% | 2.2% | -0.5% |
| 5/25/2023 | 4.3% | 5.4% | 9.0% |
| 3/3/2023 | 1.6% | -0.9% | 4.6% |
| 12/9/2022 | 1.0% | -4.5% | 0.3% |
| 9/23/2022 | -4.3% | -1.7% | -1.8% |
| 5/26/2022 | 1.2% | 2.4% | 0.8% |
| 3/4/2022 | -1.4% | -0.1% | 8.0% |
| 12/9/2021 | 6.6% | 5.4% | -1.1% |
| 9/23/2021 | 3.3% | -0.8% | 6.5% |
| 5/27/2021 | -2.4% | 0.0% | 2.3% |
| SUMMARY STATS | |||
| # Positive | 11 | 9 | 11 |
| # Negative | 9 | 11 | 9 |
| Median Positive | 1.9% | 2.4% | 4.6% |
| Median Negative | -2.4% | -2.9% | -1.8% |
| Max Positive | 6.6% | 5.5% | 10.9% |
| Max Negative | -7.6% | -13.2% | -10.7% |
Correlation Between 1D, 5D and 21D Historical Returns
A relatively less risky strategy (though not useful if the correlation is low) is to understand the correlation between short-term and medium-term returns post earnings, find a pair that has the highest correlation, and execute the appropriate trade. For example, if 1D and 5D show the highest correlation, a trader can position themselves “long” for the next 5 days if the 1D post-earnings return is positive. Here is some correlation data based on a 5-year and a 3-year (more recent) history. Note that the correlation 1D_5D refers to the correlation between 1D post-earnings returns and subsequent 5D returns.
| History | 1D_5D | 1D_21D | 5D_21D |
|---|---|---|---|
| 5Y History | 4.4% | -4.8% | -21.5% |
| 3Y History | 32.1% | 23.4% | -18.8% |
Is There Any Correlation With Peer Earnings?
Sometimes, peer performance can have an influence on post-earnings stock reaction. In fact, the pricing-in might begin before the earnings are announced. Here is some historical data on the past post-earnings performance of Costco Wholesale stock compared with the stock performance of peers that reported earnings just before Costco Wholesale. For fair comparison, peer stock returns also represent post-earnings one-day (1D) returns.
| 1D Return | Peer Post-Earnings 1D Return | ||||
|---|---|---|---|---|---|
| COST Earnings Dates | COST | WMT | AMZN | TGT | HD |
| 3/5/2026 | 1.6% | -1.2% | -1.7% | 5.0% | -5.9% |
| 12/11/2025 | -0.0% | 7.9% | N/A* | 12.7% | 6.9% |
| 5/29/2025 | 3.1% | 0.8% | 8.1% | 2.0% | -2.3% |
| 3/6/2025 | -6.1% | -2.6% | -16.0% | -2.6% | -2.9% |
| 12/12/2024 | 0.1% | 8.6% | N/A* | 11.1% | N/A* |
| 5/30/2024 | -0.7% | 1.4% | N/A* | 4.6% | -2.7% |
| 3/7/2024 | -7.6% | 3.0% | N/A* | 1.8% | 4.5% |
| 12/14/2023 | 4.4% | -2.1% | N/A* | 8.2% | N/A* |
| 5/25/2023 | 4.3% | -3.5% | 4.7% | -12.6% | 1.6% |
| 3/3/2023 | 1.6% | -4.5% | -16.0% | -1.5% | 1.0% |
| 12/9/2022 | 1.0% | -1.1% | N/A* | -2.1% | 3.4% |
| 5/26/2022 | 1.2% | -4.1% | -23.2% | 1.0% | 0.6% |
| 3/4/2022 | -1.4% | 2.8% | 4.9% | 2.1% | 2.6% |
| 12/9/2021 | 6.6% | -2.9% | N/A* | -6.4% | 5.3% |
| CORRELATION | -11.5% | 1.9% | -17.4% | 13.4% | |
* N/A indicates that the peer reported earnings after COST
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