Costco (COST) RSI History
Historical oversold and overbought episodes, duration, and forward returns.
COST RSI at a glance
As of September 1, 2026, Costco (COST) is in a neutral RSI zone.
| Current RSI zone | Neutral |
|---|---|
| Last oversold episode | December 22, 2025 |
| Last overbought episode | May 18, 2026 |
| Oversold episodes | 9 |
| Overbought episodes | 29 |
| History since | April 2022 |
COST oversold history
COST’s most recent oversold episode began on December 22, 2025 and lasted 1 day. There have been 9 COST oversold episodes since April 2022. The median duration was 2 days, and the longest episode lasted 7 days.
What happened after COST became oversold?
Across those 9 episodes, COST was higher 20 trading days later in 8 cases (89%), with a median return of +2.53%.
| After becoming oversold | Sample | COST higher | Median return |
|---|---|---|---|
| 5 trading days | 9 | 7 of 9 (78%) | +1.26% |
| 10 trading days | 9 | 7 of 9 (78%) | +4.82% |
| 20 trading days | 9 | 8 of 9 (89%) | +2.53% |
| 50 trading days | 9 | 7 of 9 (78%) | +4.96% |
| 100 trading days | 9 | 5 of 9 (56%) | +8.46% |
Every COST oversold episode
| Episode began | Duration | 5d | 10d | 20d | 50d | 100d |
|---|---|---|---|---|---|---|
| Dec 22, 2025 | 1 day | +1.84% | +3.83% | +14.84% | +17.58% | +26.82% |
| Jul 30, 2025 | 1 day | +4.57% | +5.68% | +2.51% | +1.80% | −7.49% |
| Jul 28, 2025 | 1 day | +2.43% | +6.01% | +0.95% | −1.92% | −7.38% |
| Jul 24, 2025 | 1 day | +0.63% | +4.82% | +3.99% | −1.84% | −7.58% |
| Mar 13, 2025 | 4 days | +0.54% | +5.40% | +8.27% | +13.38% | +9.04% |
| Dec 19, 2022 | 2 days | −0.03% | −0.45% | +2.37% | +3.81% | +9.88% |
| Sep 23, 2022 | 3 days | +1.26% | +0.37% | +2.53% | +4.96% | +8.46% |
| May 18, 2022 | 7 days | +2.49% | +13.56% | +5.21% | +27.56% | +10.12% |
| May 11, 2022 | 2 days | −12.20% | −10.01% | −3.48% | +8.19% | −0.43% |
COST overbought history
COST’s most recent overbought episode began on May 18, 2026 and lasted 2 days. There have been 29 COST overbought episodes since April 2022. The median duration was 4 days, and the longest episode lasted 17 days.
What happened after COST became overbought?
Across those 29 episodes, COST was higher 20 trading days later in 21 cases (72%), with a median return of +4.14%.
| After becoming overbought | Sample | COST higher | Median return |
|---|---|---|---|
| 5 trading days | 29 | 20 of 29 (69%) | +1.58% |
| 10 trading days | 29 | 20 of 29 (69%) | +2.14% |
| 20 trading days | 29 | 21 of 29 (72%) | +4.14% |
| 50 trading days | 29 | 23 of 29 (79%) | +3.60% |
| 100 trading days | 28 | 24 of 28 (86%) | +9.21% |
Sample sizes vary by horizon because newer episodes may not yet have enough subsequent trading days.
Every COST overbought episode
| Episode began | Duration | 5d | 10d | 20d | 50d | 100d |
|---|---|---|---|---|---|---|
| May 18, 2026 | 2 days | −6.83% | −11.35% | −8.34% | −11.36% | Pending |
| Feb 6, 2026 | 3 days | +1.73% | −1.51% | +0.41% | +0.46% | −4.94% |
| Jan 14, 2026 | 13 days | +2.65% | +0.20% | +5.18% | +3.60% | +1.99% |
| Jan 12, 2026 | 1 day | +2.25% | +2.88% | +3.13% | +3.51% | +3.19% |
| Feb 19, 2025 | 1 day | −2.88% | −1.39% | −14.92% | −5.98% | −8.81% |
| Feb 3, 2025 | 15 days | +5.69% | +5.11% | +3.20% | −2.77% | −1.82% |
| Dec 6, 2024 | 3 days | −0.33% | −3.88% | −7.18% | +4.39% | +2.49% |
| Dec 3, 2024 | 2 days | +1.14% | −0.01% | −7.37% | +7.64% | +1.37% |
| Nov 26, 2024 | 1 day | +2.00% | +2.39% | −1.58% | +9.06% | +0.52% |
| Nov 8, 2024 | 3 days | −3.89% | +2.14% | +4.67% | −0.44% | −3.67% |
| Aug 27, 2024 | 1 day | −2.08% | −0.94% | −0.05% | −0.93% | +4.08% |
| Jul 5, 2024 | 6 days | −4.83% | −5.37% | −7.05% | +2.65% | +8.79% |
| Jun 4, 2024 | 17 days | +2.65% | +5.24% | +4.26% | +6.19% | +7.87% |
| May 30, 2024 | 1 day | +3.35% | +3.76% | +4.25% | +6.07% | +9.74% |
| May 24, 2024 | 5 days | +0.70% | +4.77% | +5.65% | +0.21% | +9.49% |
| May 15, 2024 | 8 days | +1.88% | +3.59% | +7.49% | +3.77% | +13.30% |
| May 9, 2024 | 4 days | +1.80% | +2.22% | +8.54% | +9.38% | +12.93% |
| May 7, 2024 | 1 day | +0.85% | +3.84% | +8.17% | +8.66% | +15.10% |
| Feb 22, 2024 | 15 days | +1.29% | +6.97% | +1.11% | +1.46% | +15.42% |
| Feb 14, 2024 | 7 days | +1.69% | +3.01% | +1.35% | +1.13% | +22.65% |
| Feb 1, 2024 | 12 days | +2.79% | +2.84% | +6.38% | +1.96% | +21.82% |
| Jan 30, 2024 | 1 day | +1.58% | +2.08% | +6.89% | +4.66% | +21.41% |
| Jan 10, 2024 | 13 days | +2.16% | +1.06% | +7.80% | +9.38% | +23.36% |
| Dec 21, 2023 | 8 days | +1.49% | +1.74% | +5.72% | +19.07% | +22.32% |
| Dec 7, 2023 | 13 days | +3.25% | +8.87% | +10.77% | +21.21% | +22.99% |
| Nov 15, 2023 | 1 day | −1.29% | −0.68% | +5.70% | +20.09% | +25.69% |
| Jul 17, 2023 | 14 days | +1.98% | +1.39% | +1.54% | +0.19% | +10.26% |
| Jun 30, 2023 | 6 days | −2.11% | +2.71% | +4.14% | +3.99% | +8.93% |
| Feb 1, 2023 | 2 days | −2.55% | −1.11% | −6.06% | −4.97% | +2.79% |
For recent episodes, forward-return horizons that have not yet occurred are shown as Pending.
How these numbers are measured
An oversold episode begins when COST enters an oversold state and ends when it returns to a non-oversold state. Continuous oversold readings are treated as one episode. Overbought episodes are defined the same way.
Episode duration is measured in calendar days. Forward returns are measured 5, 10, 20, 50, and 100 trading days after the first day of each episode. Stock prices are split- and dividend-adjusted.
Historical observations are descriptive and do not predict future performance.
- Source
- TickerDB
- Data frequency
- Daily end-of-day
- Last updated
- September 1, 2026
- History since
- April 2022
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