How big do small caps move on earnings?
How far does a stock move the day after it reports, by company size?
The answer
Small caps move about 7% on earnings day, roughly 1.5× a large cap. About 1 in 14 reports moves the stock 20% or more.
68,529 cases tested.
The numbers
| Company size | Average move | Moved 10%+ | Moved 20%+ | In the opening gap |
|---|---|---|---|---|
| Micro caps (under $300M)14,207 reports | 7% | 23% | 7% | 61% |
| Small caps ($300M–$2B)21,557 reports | 7% | 24% | 7% | 68% |
| Mid caps ($2B–$10B)18,734 reports | 6% | 18% | 4% | 73% |
| Large caps ($10B+)14,031 reports | 5% | 11% | 2% | 77% |
What it means for a trader
Smaller companies move more, but most of each move is already in the opening price. If you plan to act on earnings, you are mostly deciding before the report, not after.
How it was tested
Every earnings report (SEC Form 8-K, item 2.02) since 2021 for US-listed stocks over $2. The move is from the prior close to the close of the first full trading day after the report. Company size is market value just before the report.
History, not predictions. Not investment advice.