Costco's press release moved COST -1.69%
COST moved -0.34% in five minutes and -1.69% by market close — about 1691× Costco's median close-day move.
· GlobeNewswire · Press release · Realized reaction, point-in-time, zero look-ahead.
Costco Wholesale Corporation Reports September Sales Results
Via GlobeNewswire
How COST reacted after the announcement.
| Horizon | Reaction | COST median |
|---|---|---|
| 30 sec | -0.16% | — |
| 1 min | -0.39% | — |
| 5 min | -0.34% | — |
| 10 min | -0.49% | — |
| 30 min | -1.01% | -0.02% |
| 60 min | -1.30% | — |
| 90 min | -1.56% | — |
| 120 min | -1.24% | — |
| to close | -1.69% | +0.00% |
- +1%
- never traded
- +2%
- never traded
- +3%
- never traded
- +5%
- never traded
- -1%
- 29 min
- -2%
- never traded
- -3%
- never traded
- -5%
- never traded
A hatched rung is a threshold the price never touched inside the measured window — not a missing measurement. Most news never moves a large-cap by 5% either way, so a mostly empty ladder is the finding, not a gap in the data.
| Held for | Return |
|---|---|
| D+1 | -1.64% |
| D+2 | -2.14% |
| D+3 | -2.06% |
| D+4 | -1.53% |
| D+5 | -2.33% |
| 1M | +2.68% |
| 3M | +3.13% |
| 6M | +6.24% |
| 12M | +3.79% |
Each row is measured from the price at the news to that horizon independently, so the ladder is not cumulative and a later row can sit above an earlier one. “Available” is a date, not a gap: that horizon has not elapsed yet for this event, and it is computed from the event’s own timestamp rather than from the data. An em dash is the other case — the horizon passed and no return was recorded.
Five minutes after the news, COST had moved -0.34%; by the close it stood at -1.69% — the two readings agree in direction.
Impact: Negative. Reaction = percent move vs. the price at the news timestamp. Sources below.
COST’s news landed in the after-hours window; the main session closed -1.69%.
- Mainprior session
- After-hours4:00 – 8:00 PM
- Overnightno tape
- Pre-market4:00 – 9:30 AM
- Main session9:30 AM – 4:00 PM
Segment widths are fixed, so two events on different days sit in comparable places. Hatched segments are real elapsed time with no tape to measure — the overnight halt is not a gap in the data. This event carries no intraday receipt time, so it is not pinned to a minute.
| Window | What it answers | Anchor price | Result | vs S&P 500 |
|---|---|---|---|---|
| All | From the news to the first main-session close, across every session in between. | 908.50re-anchored to the first print after the news | -1.64% | — |
| After-hours | The move between the closing bell and the overnight halt. | — | not measured | — |
| Pre-market | The move between the pre-market open and the opening bell. | — | not measured | — |
| Main | The move inside the regular session, from the news to the close. | 909.00the price at the news | -1.69% | -1.74% |
The main-session result is measured upstream against the price at the news; the all-sessions result is computed here from its own anchor and close, so the two can differ in the last decimal. The adjusted column subtracts the S&P 500’s move over the same main-session span — there is no index anchor for the all-sessions span, so that cell stays empty rather than borrowing this one. After-hours and pre-market are measured upstream but populate on a small minority of events, so this page does not request them. Those rows are unmeasured, not empty.
The same event measured across every session8
| Horizon | Reaction |
|---|---|
| 30 sec | +0.04% |
| 1 min | -0.04% |
| 5 min | -0.06% |
| 10 min | +0.08% |
| 30 min | +0.28% |
| 60 min | +0.27% |
| 90 min | +0.24% |
| 120 min | +0.17% |
Where this COST event came from, and what the tape did with it.
Costco issued a press release, carried via GlobeNewswire, on Oct 9, 2024. It was one of 2 Costco headlines News Quantified labeled that day, so its measurement window overlaps with the others on a shared tape. The same session also carried Costco's "Form 10-K COSTCO WHOLESALE CORP For: Sep 01", each measured on its own clock.
Against the price at the news timestamp, COST moved -0.34% after five minutes and -1.69% by the close — about 1691× Costco's median close-day move of +0.00% across 2,000+ events. Because several releases shared that day, their measurement windows overlap and no single headline cleanly owns the move.
This is the alert you’d have received.
Costco Wholesale Corporation Reports September Sales Results
Track COST and you’ll get one email like this the next time it moves on news — the headline, the measured reaction, and how it compares to COST’s baseline. Nothing else.
Set up COST alerts →How this compares to COST’s usual reaction.
Across 2,000+ labeled events, COST’s median 30-minute reaction to all news is -0.02% (48% up); by the close it is +0.00%.
| Middle 50% of COST reactions | -0.42% to +0.30% |
|---|---|
| Median reaction (30-min) | -0.02% |
| This event | -1.01% |
| Measured reactions | 2,000+ |
Half of all Costco news events land between -0.42% and +0.30% at 30 minutes; this one is a single draw from that distribution.
You just saw one reaction. There are 26M+ more.
See the full COST reaction history →COST’s session ranged -1.89% to +0.11% against the price at the news.
725.5K shares against a 30-day average of 947.1K.
What the average share actually traded at across the session, rather than at any one print.
The close moved -1.69% against a 20-day average true range of 16.18. COST carries no market-cap or price-to-earnings figure on this record, and no short interest, so none is shown.
Email me when COST moves on news.
One email per qualifying move — the headline, the measured reaction, and how it compares to COST's baseline. Nothing else.
How comparable COST events have landed.
Across 5 other recent Costco press release events, the median close-day reaction was -1.08%. Each is measured the same way, from its own news timestamp.
8 more COST events, each measured the same way.
Recent COST events, each with its measured reaction8
| Date | Headline | 5-min | To close |
|---|---|---|---|
| Form 8-K COSTCO WHOLESALE CORP For: Sep 24 | +2.36% | +3.92% | |
| Form 8-K COSTCO WHOLESALE CORP For: Jul 07 | -0.89% | -1.83% | |
| Form 11-K COSTCO WHOLESALE CORP For: Dec 31 | -0.10% | -1.24% | |
| Form 10-Q COSTCO WHOLESALE CORP For: May 10 | +0.08% | -1.48% | |
| Form S-3ASR COSTCO WHOLESALE CORP | +0.08% | -1.48% | |
| Form SD COSTCO WHOLESALE CORP | -1.37% | -3.07% | |
| Costco Wholesale Corporation Reports Third Quarter and Year-To-Date Operating Results For Fiscal 2026 | -1.37% | -3.07% | |
| Form 8-K COSTCO WHOLESALE CORP For: May 28 | -1.37% | -3.07% |
That same day, across the market8
Same measurement, same clock, different names — each headline measured from its own news timestamp, point-in-time.
Peer tickers, measured the same way4
Every US ticker is measured the same way, from its own news timestamp. Browse all tickers →
COST carried 1 other record that day.
Each was measured the same way, from its own timestamp.
| Record | Event | 5-min | To close |
|---|---|---|---|
| Form 10-K COSTCO WHOLESALE CORP For: Sep 01 | SEC filing · Form 10-K | -0.13% | +1.89% |
How the numbers are made.
How was COST's -0.34% reaction measured?
From the news timestamp, not the trading day: News Quantified takes the last trade before this press release as the base price and measures the move five minutes of trading later — point-in-time, zero look-ahead. The same clock produced the -1.69% to-close figure.
What is Costco's median reaction, and how does this event compare?
Costco's median is drawn from 2,000+ labeled events; at 30 minutes it sits at -0.02%, and +0.00% by the close. This event's move is one draw from that distribution — ordinary or outlier, the chart's median ticks show which.
2 Costco headlines shared Oct 9, 2024. Whose reaction is this?
Each of the 2 same-day Costco events is measured from its own timestamp, but their windows overlap on one tape, so we show the cluster rather than pretending a single headline owns the move.
Does -1.69% predict Costco's next reaction?
No. -1.69% is a realized fact about Oct 9, 2024, not a forecast. Past reactions describe a distribution; they say nothing certain about any future move.
How to cite this reaction.
News Quantified. "Costco Wholesale Corporation Reports September Sales Results." COST realized price reaction, Oct 9, 2024. Retrieved from https://newsquantified.com/tickers/cost/news/costco-wholesale-corporation-reports-september-sales-results-2024-10-09
Canonical URL: https://newsquantified.com/tickers/cost/news/costco-wholesale-corporation-reports-september-sales-results-2024-10-09
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