MGNI insider buying and selling clusters
How this is computed
Four MGNI insiders sold $1.45M of shares between 2026-09-14 and 2026-09-17, reported to the SEC by 2026-09-18. The cluster was last detected in the 2026-10-14 snapshot, and no cluster is active on MGNI in the 2026-10-22 snapshot.
Kresmion groups open-market Form 4 purchases and sales (codes P and S) into clusters of three or more distinct insiders trading the same direction on one ticker inside a rolling 30-day window, and sums the value each filing reports.
Latest cluster per direction1 shown, newest first
| Direction | Status | Trade dates | Insiders | Trades | Filed value | Senior titles among the filers | First detected | Latest filing read by |
|---|---|---|---|---|---|---|---|---|
| Sales | Last detected 2026-10-14 | 2026-09-14 to 2026-09-17 | 4 | 4 | $1.45M | none matched | 2026-08-13 | 2026-09-18 |
The trades behind these clusters4 most recent of 4, open-market codes P and S
| Insider | Direction | Code | Trade date | On EDGAR by | Shares | Price | Value | 10b5-1 plan | Filing |
|---|---|---|---|---|---|---|---|---|---|
Knopper Douglas S Director | Sale | S | 2026-09-17 | 2026-09-18 | 37,337 | $26.28 | $981K | yes | Form 4 |
Caine Paul Director | Sale | S | 2026-09-17 | 2026-09-18 | 7,500 | $26.50 | $199K | yes | Form 4 |
Spillane Robert F Director | Sale | S | 2026-09-14 | 2026-09-17 | 10,363 | $23.76 | $246K | no | Form 4 |
Buonasera David CHIEF TECHNOLOGY OFFICER | Sale | S | 2026-09-14 | 2026-09-17 | 1,165 | $24.00 | $28K | yes | Form 4 |
Full MGNI history after sign-in
This public page shows the latest cluster per direction and at most 10 trades. Signed in, the same address lists every cluster episode on MGNI (2 on file), all 22 open-market trades from the last 24 months with the shares held after each trade and the share of the stake traded, and what the share price did in the 30 days after each episode.
Method and limitationsread before using the numbers
- A cluster is three or more distinct insiders filing open-market trades in the same direction on one ticker inside a rolling 30-day window. Kresmion detects clusters once a day at 02:30 UTC from SEC Form 4 filings.
- Only Form 4 transaction codes P (open-market purchase) and S (open-market sale) with a named insider and a filed value count. Option exercises, grants, gifts and tax withholding carry no direction and are not counted.
- Trade dates come from the filings. A Form 4 is due within two business days of the trade. "On EDGAR by" is the date Kresmion first stored the filing, so it was public on or before that date; the SEC filing index linked on each row shows the exact filing date. "Reported to the SEC by" is the latest of those dates across a cluster's filings.
- Filed value is shares times the price reported on the Form 4, summed per cluster. Senior titles are CEO, CFO, President and Chairman as matched in the filer's stated role; a title such as "President, Global Sales" counts as President.
- Rule 10b5-1 plan trades are flagged where the filing carries the flag, which Form 4 has recorded since the April 2023 amendments; older filings show no flag. Disclosure under Section 16 does not imply impropriety. Read the filings on EDGAR before drawing conclusions.
Full methodology · All insider clusters in the latest snapshot
Cite this data
Kresmion groups open-market Form 4 purchases and sales (codes P and S) into clusters of three or more distinct insiders trading the same direction on one ticker inside a rolling 30-day window, and sums the value each filing reports.
Upstream: US SEC EDGAR Form 4 filings (MAGNITE, INC.)
Kresmion, "MGNI insider Form 4 cluster snapshot", data as of 2026-10-22, https://kresmion.com/tools/insider-clusters/MGNI. Upstream data: US SEC EDGAR Form 4 filings (MAGNITE, INC.).
Link to this data (HTML):
<a href="https://kresmion.com/tools/insider-clusters/MGNI">MGNI insider Form 4 cluster snapshot (Kresmion)</a>