COIN insider net‑selling extremes → forward 20‑day return (weekly, top decile)
After weeks of heavy insider selling, COIN has tended to drift lower over the next month — but the signal is far from crystal clear. The top-decile selling weeks averaged a forward 20-day return of -4.4%, while all other weeks returned +6.0% — a gap of more than ten percentage points. Yet with only 15 extreme-selling weeks in 148, the result carries a p-value of 0.062, meaning it could be noise about six times in a hundred.
This study tests whether insider net-selling extremes, as reported on Form-4, reliably precede below-baseline returns — the idea that smart money exits near local peaks. The directional support is there, but the evidence is borderline. For the full breakdown of data, charts, and the reasoning behind this finding, read the analysis below.
For COIN over the past ~3 years, do weeks with top-decile net insider selling as reported on Form-4 predict below-baseline forward 20-day returns, signaling that insiders reliably offload near local peaks? Thesis: Consistent insider selling marks price tops, so the stock underperforms in the following month as the smart money quietly exits.
How this was measured
Form‑4 insider transactions for COIN (last ≈3 years) are aggregated to calendar weeks (Mon‑Sun). Net selling per week = total disposal notional − total acquisition notional, with zero filled for weeks with no insider activity. Weeks are ranked by net selling; the top decile (highest selling) is tagged as heavy‑selling weeks. For every calendar week, the forward 20‑trading‑day return is measured from the close of the first trading day on or after that week’s Friday. A Welch two‑sample t‑test (unequal variance) compares the forward returns of heavy‑selling weeks against the remaining (non‑top‑decile) weeks. The thesis is that heavy net selling signals insider distribution near local highs, predicting subsequent underperformance.
The key numbers
Reading the numbers
After extreme insider selling weeks, COIN's average 20-day return was -4.4%, versus +6.0% for all other weeks — a roughly 10-percentage-point gap. But that gap just misses conventional statistical significance (p=0.06), so it's suggestive, not conclusive.
The charts
This histogram stacks the frequency of forward 20-day returns for heavy-selling weeks (orange) against all other weeks (blue). The orange bars cluster below zero, meaning most heavy-selling weeks were followed by negative returns, while the blue bars stretch further into positive territory. The key takeaway is that the two distributions clearly separate at the zero line, but the small number of orange bars (just 15 weeks) makes the pattern fragile.
The box plot lays out the full return distribution for each group. The heavy-selling box sits entirely below zero (median negative) with a mean of -4.4%, while the rest group's box straddles zero with a mean of +6.0%. The most telling detail is that the heaviest-selling weeks' entire middle 50% of returns is negative, whereas most other weeks see a mix of gains and losses. This aligns with the thesis that insiders offload near peaks, but the wide whiskers and small heavy-selling sample (15 vs 133) remind us not to over-interpret.
Top‑decile heavy‑selling weeks (sorted by net selling high→low)
| week_start | anchor_date | net_selling_usd | fwd20_return |
|---|---|---|---|
| 2024-11-18 | 2024-11-22 | 332,784,358 | -0.1144 |
| 2025-07-14 | 2025-07-18 | 219,448,062 | -0.242 |
| 2024-11-11 | 2024-11-15 | 175,701,059 | 0.0351 |
| 2025-06-23 | 2025-06-27 | 164,317,878 | 0.0757 |
| 2024-03-04 | 2024-03-08 | 143,640,989 | 0.008 |
| 2024-02-26 | 2024-03-01 | 137,385,527 | 0.2218 |
| 2025-11-03 | 2025-11-07 | 103,076,229 | -0.113 |
| 2024-12-02 | 2024-12-06 | 60,364,121 | -0.2194 |
| 2025-11-10 | 2025-11-14 | 57,025,478 | -0.1287 |
| 2026-02-02 | 2026-02-06 | 55,074,317 | 0.1923 |
| 2026-01-12 | 2026-01-16 | 43,876,969 | -0.3137 |
| 2023-12-18 | 2023-12-22 | 42,749,690 | -0.3067 |
| 2023-12-11 | 2023-12-15 | 34,051,596 | -0.0996 |
| 2026-02-16 | 2026-02-20 | 30,233,106 | 0.162 |
| 2024-05-13 | 2024-05-17 | 29,369,691 | 0.1819 |
The takeaway
There's a pattern suggesting that COIN's worst insider-selling weeks precede a soft month, but it's not statistically airtight. Over 148 weeks, the top-decile selling weeks (15 total) averaged a forward 20-day return of -4.4%, while the rest of the weeks averaged +6.0% — a gap of over 10 percentage points. But with a p-value of 0.062, that gap could be random about 6 times out of 100, which is borderline and not conclusive by usual standards. Given only 15 heavy-selling weeks, the result is more of a suggestive lean than a reliable signal: one or two extremes (like the -24% after July 2025's heavy selling) are pulling the average down. For the thesis that insiders sell near local peaks, the directional support is there, but the evidence isn't strong enough to trade on alone.
The fine print
- Only 15 heavy-selling weeks; the average return is vulnerable to a few extreme events (e.g., the -24% week in July 2025).
- Forward 20-day windows overlap across consecutive weeks, violating independence and making the p-value approximate.
- The top-decile threshold is based on the full dataset; out-of-sample performance may differ.
- Form-4 filings have a 1-2 day lag; the assumed Friday close timing may not reflect when the market actually learns of the sales.