FlinchLab · SEC 8-K filings
Does company news move the stock price?
Public companies must disclose material news through SEC 8-K filings. We took every 8-K from 660 companies over the last several years, read what each one actually said, sorted them into categories finer than the official filing codes, and measured what the share price did next.
Typical earnings-day swing
6.10%
6.10% is how far the price typically moves — in either direction. The average direction is -0.15%, which is effectively a coin flip: good and bad news cancel out.
n=11,241 · earnings reports
29,331 news events measured · 524 left out for insufficient price history
Every figure on this page comes out of one file. It holds the categories below the official codes, every validated finding with both out-of-sample checks, and the full grid across company size, filing time and disclosure lag.
Download the dataset →Why the official filing codes are not enough
One SEC code covers every earnings release. That single bucket holds companies raising guidance and companies cutting it, and those move the share price in opposite directions, so the average across the code is close to nothing. We read the text of each filing and split it into what it actually says. The categories below the official codes are where the real differences live, and they are the part of this that public filings do not give you.
Every label was checked twice: once structurally, and once by having a model from a different lab re-label a sample so the two could be compared. Agreement is reported as a number rather than asserted, and categories that did not clear the bar are not published. How that was measured →
Slice by
Index membership as a proxy for size. Small-cap reactions are consistently larger — thinner coverage and thinner books.
How each type of news moves the stock
For every kind of company news, the typical price move afterward — and whether that pattern is real or just noise. Click a column to sort by it.
Typical distance moved, ignoring which way. This is the quantity that is large and reliable. Significance here comes from a separate magnitude test, corrected in its own family.
Every type of news, combined ALL · All item codes pooled | 29331 | 3.50%*** | 4.11%*** | 5.48%*** | 4.83% |
Attached financial documents 9.01 · Financial Statements and Exhibits | 24056 | 3.86%*** | 4.46%*** | 5.74%*** | 4.79% |
Reported earnings 2.02 · Results of Operations and Financial Condition | 11241 | 6.10%*** | 6.62%*** | 7.49%*** | 4.63% |
Shared news with investors (not earnings) 7.01 · Regulation FD Disclosure | 8420 | 3.47%*** | 4.07%*** | 5.45%*** | 4.80% |
An executive or board member left or joined 5.02 · Departure/Election of Directors or Officers | 6053 | 2.21%*** | 2.89%*** | 4.65%*** | 5.24% |
Other company news 8.01 · Other Events | 5923 | 2.76%*** | 3.31%*** | 4.87%*** | 4.86% |
Signed a major business deal 1.01 · Entry into a Material Agreement | 3204 | 2.37%*** | 3.04%*** | 4.59%*** | 5.01% |
Shareholders voted on something 5.07 · Submission of Matters to a Vote of Security Holders | 2666 | 1.65% | 2.41% | 4.29% | 5.07% |
Took on new debt 2.03 · Creation of a Direct Financial Obligation | 1833 | 1.92%*** | 2.62%*** | 4.25% | 4.89% |
Changed its own bylaws 5.03 · Amendments to Articles of Incorporation or Bylaws | 947 | 1.86%*** | 2.63%*** | 4.15% | 4.90% |
Bought or sold a company 2.01 · Completion of Acquisition or Disposition | 321 | 2.15%*** | 3.23%*** | 5.91%*** | 6.04% |
Ended a major business deal 1.02 · Termination of a Material Agreement | 319 | 2.10%*** | 2.94%*** | 4.55% | 5.07% |
Sold new stock privately 3.02 · Unregistered Sales of Equity Securities | 318 | 2.84%*** | 3.70%*** | 5.45%* | 5.94% |
Announced layoffs or a shutdown 2.05 · Costs Associated with Exit or Disposal Activities | 187 | 4.56%*** | 5.23%*** | 6.33%*** | 5.76% |
Changed shareholder rights 3.03 · Material Modification to Security Holder Rights | 164 | 2.14%*** | 2.79%* | 4.28% | 4.88% |
12 more news types in the full table, plus every company size, filing time and disclosure lag.
Get the full dataset →Showing 15 of 27 news types for All filings. Click any column to sort by it. A star (*, **, ***) means the pattern held up after checking it wasn't just random chance — more stars is more confident. Rows marked “too few” (under 10 events) show the count honestly and leave the averages blank (“—”) — with that little data an average is one or two companies, not a pattern. A blank never means zero. How this is calculated →
Does the news leak out early, or hit during trading?
Every stock move happens in one of two places: the jump between yesterday's close and today's open (before most people can react), or the move during the trading day itself. Same-day reaction only; groups with fewer than 10 events are left out.
How much data sits behind each type of news
How many filings of each type came from large, mid-size and small companies. Read this before trusting a small cell above — it shows where the sample is thin. Darker means more events, and the count is always printed, so the shading is an orientation aid and never the only way to read a cell.
| Type of news | Large | Mid-size | Small |
|---|---|---|---|
| Attached financial documents9.01 | 2760 | 9756 | 11540 |
| Reported earnings2.02 | 1262 | 4632 | 5347 |
| Shared news with investors (not earnings)7.01 | 776 | 3411 | 4233 |
| An executive or board member left or joined5.02 | 725 | 2427 | 2901 |
| Other company news8.01 | 850 | 2252 | 2821 |
| Signed a major business deal1.01 | 215 | 1405 | 1584 |
| Shareholders voted on something5.07 | 291 | 1088 | 1287 |
| Took on new debt2.03 | 115 | 854 | 864 |
| Changed its own bylaws5.03 | 161 | 374 | 412 |
| Bought or sold a company2.01 | 20 | 122 | 179 |
| Ended a major business deal1.02 | 40 | 140 | 139 |
| Sold new stock privately3.02 | 22 | 130 | 166 |
| Announced layoffs or a shutdown2.05 | 28 | 57 | 102 |
13 more news types in the full dataset.
Click here to download the dataset →