Costco's SEC filing (Form 10-K) — COST's reaction is being measured
COST's realized reaction is still being measured.
· SEC EDGAR · SEC filing · Form 10-K · Realized reaction, point-in-time, zero look-ahead.
Form 10-K COSTCO WHOLESALE CORP For: Aug 30
Via SEC EDGAR
Reaction is being measured.
This event is recent. News Quantified labels the realized price reaction once the trading sessions after the news complete — point-in-time, with zero look-ahead. The measured move will appear here, and below in COST’s reaction history.
COST’s news landed in the pre-market window; the main session closed +0.07%.
- 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 |
|---|---|---|---|
| All | From the news to the first main-session close, across every session in between. | 935.05re-anchored to the first print after the news | +0.07% |
| 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. | — | not measured |
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. 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 | +0.32% |
| 1 min | +0.42% |
| 5 min | +0.42% |
| 10 min | +0.43% |
| 30 min | +0.29% |
| 60 min | +0.80% |
| 90 min | +0.80% |
| 120 min | +0.07% |
Where this COST event came from, and what the tape did with it.
Costco filed Form 10-K with the SEC on Oct 7, 2026. It was the only Costco headline News Quantified labeled that day.
Against the price at the news timestamp, COST's reaction is still being measured.
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% |
| 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 →What the COST tape carried around this event.
The 20-day average true range into this session was 15.46. 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 SEC filing events, the median close-day reaction was -1.48%. Each is measured the same way, from its own news timestamp.
| 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% |
8 more COST events, each measured the same way.
Recent COST events, each with its measured reaction8
That same day, across the market2
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 →
How the numbers are made.
How was COST's 5-minute reaction measured?
From the news timestamp, not the trading day: News Quantified takes the last trade before this SEC filing (Form 10-K) as the base price and measures the move five minutes of trading later — point-in-time, zero look-ahead. The same clock produced the 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.
Only one Costco headline was labeled Oct 7, 2026. How is it isolated?
It was the only Costco headline labeled that day, so its window has no same-day overlap — the move is measured cleanly from its own timestamp.
Does a measured reaction predict Costco's next reaction?
No. a measured reaction is a realized fact about Oct 7, 2026, not a forecast. Past reactions describe a distribution; they say nothing certain about any future move.
How to cite this reaction.
News Quantified. "Form 10-K COSTCO WHOLESALE CORP For: Aug 30." COST realized price reaction, Oct 7, 2026. Retrieved from https://newsquantified.com/tickers/cost/news/form-10-k-costco-wholesale-for-aug-30-2026-10-07
Canonical URL: https://newsquantified.com/tickers/cost/news/form-10-k-costco-wholesale-for-aug-30-2026-10-07
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