Douglas S Knopper
CIK 1350876 · last filed 2026-09-18
Douglas S Knopper is a corporate insider who has filed 26 SEC Form 4 insider transactions across 4 companies since 2007. The most recent filing shows the insider sold $981.2K of MGNI on Sep 18, 2026. Across all open-market trades the lifetime net is −$4.3M, making them a net seller over the disclosed history. Current disclosed insider exposure totals $1.1M across reported positions.
"Disclosed insider exposure" sums this person's most-recently-reported share counts across each company they're an insider in, multiplied by the current underlying price. It is not net worth — it misses retail holdings, private investments, real estate, index funds, and any company where the person isn't an SEC-reporting insider. For informational purposes only.
Charts
Trading activity, where the exposure sits, and each trade against the stock price.
MGNI price and trades
Daily close with each Form 4 filing on this company marked: green = open-market buy, red = open-market sale, purple = grants, exercises, gifts and other non-market transactions. Marker size scales with the dollar value.
Shares held
Shares owned after each reported transaction on this company (direct holdings as reported).
Open-market buying and selling
by monthDollar value of open-market purchases (code P, up) and sales (code S, down) across all companies, by filing month. Grants, exercises and gifts are excluded.
Exposure by company
latestMost recently reported shares × current price. Faded bars (*) have had no filing in 3 years, so the person may no longer hold them. Click a bar to chart that company.
Filer Profile
708 THIRD AVENUE
NEW YORK, NY 10017
Holdings By Company
| Symbol | Role | Shares | Price | Disclosed Exposure | Lifetime OM Net | Filings | Latest Filed |
|---|---|---|---|---|---|---|---|
| MGNI | Director | 51,136 | $21.62 | $1.11M | -$4.26M | 13 | 2026-09-18 |
| RUBI | Director | 3 | $0.15 | $0 | $0 | 1 | 2020-04-03 |
| Telaria, Inc. (TLRA) Delisted | Director | 84,757 | — | — | $0 | 3 | 2019-10-17 |
| MEDIALINK WORLDWIDE INC (MDLK) Delisted | Director | — | — | — | $0 | 3 | 2009-01-06 |
Recent Filings
26 filings| Filed | Symbol | Action | Net Shares | Net $ | Link |
|---|---|---|---|---|---|
| 2026-09-18 | MGNI | Sell (S) | −37,337 | -$981.2K | EDGAR |
| 2026-09-17 | MGNI | Notice (144) | −37,337 | -$887.9K | EDGAR |
| 2026-08-07 | MGNI | Sell (S) | −37,337 | -$848.3K | EDGAR |
| 2026-08-07 | MGNI | Sell (S) | −37,337 | -$848.3K | EDGAR |
| 2026-08-06 | MGNI | Notice (144) | −19,128 | -$395.4K | EDGAR |
| 2026-08-06 | MGNI | Notice (144) | −18,209 | -$376.4K | EDGAR |
| 2026-06-17 | MGNI | Sell (S) | −37,337 | -$675.8K | EDGAR |
| 2026-06-16 | MGNI | Notice (144) | −37,337 | -$625.4K | EDGAR |
| 2026-06-10 | MGNI | Notice (144) | −10,766 | -$170.2K | EDGAR |
| 2026-06-10 | MGNI | Mixed | +3,032 | -$169.3K | EDGAR |
Notice (144 / 144/A): Form 144 is a notice of intent to sell restricted/control stock under Rule 144, filed before the sale; 144/A is an amendment. Many notices are pre-scheduled under Rule 10b5-1 plans. A Form 4 with code S typically follows within a few days when the planned sale executes; missing follow-up Form 4s suggest the notice was cancelled or modified.