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MICHAEL G. BARRETT

CIK 1100612 · CEO · last filed 2026-08-18

MICHAEL G. BARRETT is a CEO who has filed 93 SEC Form 4 insider transactions across 5 companies since 2013. The most recent filing shows the insider had shares withheld for taxes covering $257.3K of MGNI on Aug 18, 2026. Across all open-market trades the lifetime net is −$55.0M, making them a net seller over the disclosed history. Current disclosed insider exposure totals $9.3M across reported positions. 2 SEC filings were submitted jointly with YAHOO INC.

"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.

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Disclosed Exposure

$9.33M

Companies

5

Total Filings

93

Lifetime Open-Market Net

-$55.02M

Filer Profile

Reported Address
C/O THE RUBICON PROJECT, INC.
12181 BLUFF CREEK DRIVE, 4TH FLOOR
PLAYA VISTA, CA 90094
Phone
(310) 207-0272
Formerly Known As
BARRETT MICHAEL (1999–2000)
Related Filers
YAHOO INC — 2 joint filings, latest 2012-07-30
Profile details as reported on the filer's SEC submissions — for individual insiders the address is often in care of the issuer. Related filers are identified from jointly filed SEC submissions and shared reported addresses. View filings on SEC EDGAR.

Holdings By Company

Latest on-record share count from this person's most recent non-derivative Form 4 transaction in each company. Disclosed exposure = shares × current underlying price.
Symbol Role Shares Price Disclosed Exposure Lifetime OM Net Filings Latest Filed
MGNI CEO 392,670 $23.77 $9.33M -$52.80M 51 2026-08-18
OUT Director — $28.62 — $0 2 2026-06-04
RUBI CEO 28 $1.51 $42 -$2.22M 13 2020-06-05
Millennial Media Inc. (MM) Delisted President and CEO 0 — — $0 4 2015-10-23
Telaria, Inc. (TRMR) Delisted Director — $5.02 — $0 1 2013-10-01

Recent Filings

93 filings
Insider activity across all companies, newest first. Form 4 rows are post-trade confirmations (buys, sells, grants, exercises). Notice (144) rows are pre-trade notices of intent to sell restricted or control stock under Rule 144 — they may not all execute. Compare adjacent dates to see which notices became actual sales.
Filed Symbol Action Net Shares Net $ Link
2026-08-18 MGNI Tax (F) −10,404 -$257.3K EDGAR
2026-08-07 MGNI Mixed — -$4.97M EDGAR
2026-08-07 MGNI Mixed — -$4.97M EDGAR
2026-08-06 MGNI Notice (144) −293,968 -$6.68M EDGAR
2026-07-17 MGNI Mixed — -$561.6K EDGAR
2026-07-15 MGNI Notice (144) −38,596 -$785.5K EDGAR
2026-07-01 MGNI Mixed — -$1.03M EDGAR
2026-06-29 MGNI Notice (144) −75,000 -$1.46M EDGAR
2026-06-17 MGNI Mixed — -$3.10M EDGAR
2026-06-16 MGNI Notice (144) −100,000 -$1.75M EDGAR
Showing 1–10 of 93
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Form 4 codes: P = open-market purchase · S = open-market sale · A = grant/award · M = option exercise · F = tax withholding at vest · G = bona-fide gift · D = disposition to issuer · J = other (see filing footnote). Only P / S codes carry directional signal.
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.