Stock Catalyst: 1,142 SEC 8-K Filings From Eight Large Caps, and Which Ones Moved the Stock
A stock catalyst is an event that changes what investors know about a company quickly enough to move its share price, such as an earnings release, a merger or a new chief executive. In the US, most such events must be reported on the SEC's Form 8-K.
Traders use the word catalyst for anything that could make a stock jump or drop: a report, a deal, a lawsuit, a new chief executive. That list is too broad to act on. The measurement below narrows it by tying each company announcement to the filing that carried it and to the stock’s move that session, for eight of the largest US companies over more than ten years.
How it works
A price reflects what is known; a catalyst changes what is known. When a company reports results, announces a deal or loses its chief executive, investors reprice the stock on the new information.
Scheduled catalysts can be seen in advance. Earnings dates are announced, shareholder meetings are set weeks ahead, and product events are publicized. Option prices carry the known date, which is why implied volatility tends to drop once a report is out, the pattern the IV crush page measures on 251 releases.
Unscheduled catalysts cannot. A merger, a lawsuit, a resignation or a cyber incident arrives without warning. The only preparation is a position size that survives a move nobody saw coming.
What the SEC makes companies report
Form 8-K is the current report. The SEC’s form, as read on 26 Sep 2026, lists 33 items in nine sections, from Item 1.01 (entering a material agreement) to Item 9.01 (financial statements and exhibits). Unless an item says otherwise, the report is due within four business days of the event. The 8-K page explains how to read one.
Item 2.02 carries earnings. A company that publicly releases material, nonpublic information about the results of a completed quarter or year must identify the release and attach its text. The form treats exhibits under Items 2.02 and 7.01 as furnished rather than filed unless the company says otherwise.
Some items are catalysts by design, others are paperwork. Item 1.05 covers a cybersecurity incident the company judges material. Item 5.02 covers departures and appointments of directors and certain officers. Item 5.07 reports the results of shareholder votes, and Item 8.01 is an optional catch-all for events the company considers important to holders.
Scheduled and unscheduled, side by side
The filing time sets which session reacts. An 8-K accepted by EDGAR after 4:00 p.m. Eastern is priced in the next session; one accepted before the close is priced that day. Of the 394 results filings measured below, 314 were accepted after the close and 78 before the open, including all 43 of JPMorgan’s. The earnings report page covers what the release contains; the reaction session is where the catalyst shows up in the price.
Measuring against SPY strips out the market’s own move. A stock that rises 2% on a day SPY rises 2% has not reacted to its own news. Subtracting SPY’s return for the same session leaves the part specific to the company.
A worked example
Amazon filed its quarterly results as an Item 2.02 8-K, accepted at 4:06 p.m. Eastern on 30 Jul 2026. The market had closed, so the reaction session was 31 Jul 2026.
- AMZN’s total return that session: +15.32%.
- SPY’s total return the same session: +0.72%.
- The move specific to Amazon: 15.32% - 0.72% = 14.60 percentage points.
Against Amazon’s ordinary sessions that is about 19 times normal. On the 2,587 sessions from 2016 to 2026 with no Amazon 8-K, the median size of its move against SPY was 0.77%, and 14.60 / 0.77 is about 19. A position sized for an ordinary day carried many times that risk through one report.
The original data
The data: every Form 8-K filed by Apple, Microsoft, Nvidia, Amazon, Alphabet, Meta, Tesla and JPMorgan from 1 Jan 2016 to 25 Sep 2026, from SEC EDGAR, matched to daily total returns from Yahoo Finance (both downloaded 26 Sep 2026). That is 1,142 filings. Each is assigned to its reaction session using its acceptance time, and the stock’s return is measured against SPY’s. The filings are in a CSV of 8-K reaction sessions.
What the filings contained: Item 2.02 appeared on 394 of them, Item 8.01 on 343, Item 5.02 on 197, Item 7.01 on 152 and Item 5.07 on 88. Item 1.01 appeared on 55 and Item 1.05 on 1.
Results filings were the catalyst. Across 394 Item 2.02 reaction sessions, the median move against SPY was 4.04%, 5.26 times the 0.77% median of the 20,515 stock sessions with no 8-K. The move reached 5% or more in 158 of them (40.1%), against 1.86% of ordinary sessions.
Nearly everything else looked like an ordinary day. Excluding sessions that also carried a results filing, the median move was 0.83% on 315 Item 8.01 sessions, 0.79% on 190 Item 5.02 sessions, 0.74% on 88 Item 5.07 sessions and 0.94% on 77 Item 7.01 sessions. Item 1.01, new material agreements, stood out a little at 1.48% across 51 sessions. The totals by item are in a CSV of the summary by item.
The same catalyst moved each stock by a different amount. The median results-session move against SPY was 6.35% for Meta, 5.25% for Nvidia, 5.05% for Amazon, 4.94% for Tesla, 3.53% for Alphabet, 3.16% for Microsoft, 3.05% for Apple and 1.79% for JPMorgan. On sessions with no 8-K the medians were far smaller: 1.58% for Tesla, 1.28% for Nvidia, 0.81% for Meta, 0.77% for Amazon, 0.62% for Alphabet, 0.61% for Apple, 0.58% for JPMorgan and 0.53% for Microsoft. Tesla files its quarterly delivery figures under Item 2.02 as well, so it has 89 such sessions against 43 to 45 for the others.
The largest moves on record here were all results sessions: Nvidia on 11 Nov 2016 (+30.04 points against SPY), Meta on 3 Feb 2022 (-24.04) and 27 Oct 2022 (-24.02), Nvidia on 25 May 2023 (+23.50), Meta on 2 Feb 2023 (+21.83) and Tesla on 24 Oct 2024 (+21.70).
When it fails
A known catalyst can still produce no move. When results match what was expected, the price has little to adjust. Almost three in five results sessions here moved less than 5% against SPY.
Labeling any news a catalyst fails. Hundreds of filings about officers, votes and other events came and went with ordinary-sized moves. What moved these stocks was news about results, not the act of filing.
Direction is the part no one knows in advance. The six largest results moves above include four rises and two falls, each of more than 20 points. Knowing the date says nothing about the sign.
Eight giant companies are not every stock. Smaller companies were not measured here. They file under the same items, but this sample shows only how eight of the largest reacted.
The filing is not always first. News can reach the public by press release or on a call before any filing, and the form allows four business days after the event. For trading the news as it breaks, the filing is a record, not a head start.
Related
The 8-K page walks through reading the filing itself, and the earnings report page covers the release that drives most of the moves here. How to trade an earnings report turns the date into a plan, and IV crush shows what the same events do to option prices.
Before I hold a stock into any date, I check whether an earnings release falls inside the trade. If it does, size the position for a move several times the normal day, or close it before the report; a catalyst on the calendar is a risk you can see coming.
— Michael Whitman
This page is educational, not financial advice. Test every idea on your own charts before risking money.