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MATTHEW E MASSENGILL

CIK 1232826 · last filed 2026-06-22

MATTHEW E MASSENGILL is a corporate insider who has filed 123 SEC Form 4 insider transactions across 6 companies since 2007. The most recent filing, for WDC, was dated Jun 22, 2026. Across all open-market trades the lifetime net is −$45.8M, making them a net seller over the disclosed history. Current disclosed insider exposure totals $17.1M across reported positions. 101 SEC filings were submitted jointly with WESTERN DIGITAL CORP.

"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

$17.08M

Companies

6

Total Filings

123

Lifetime Open-Market Net

-$45.77M

Filer Profile

Reported Address
C/O WESTERN DIGITAL CORPORATION
5601 GREAT OAKS PARKWAY
SAN JOSE, CA 95119
Related Filers
WESTERN DIGITAL CORP — 101 joint filings, latest 2026-06-22
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
WDC Director 35,013 $441.57 $15.46M -$43.10M 79 2026-06-22
Sandisk Corp (SNDKV) Delisted Director 5,006 — — $0 1 2025-03-04
MICROSEMI CORP (MSCC) Delisted Director 0 — — -$2.67M 15 2018-05-30
GT Advanced Technologies Inc. (GTAT) Delisted Director 84,964 — — $0 4 2013-06-06
GT Advanced Technologies Inc. (SOLR) Delisted Director 26,231 $34.91 $915.6K $0 6 2010-09-13
CNXT Director 34,000 $47.76 $1.62M $0 6 2010-05-14

Recent Filings

123 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
2026-06-22 WDC Grant (A) — $0 EDGAR
2026-03-19 WDC Grant (A) — $0 EDGAR
2026-02-06 WDC Sell (S) −36,926 -$9.62M EDGAR
2026-02-05 WDC Notice (144) −36,926 -$9.95M EDGAR
2026-02-03 SNDK Notice (144/A) −2,000 -$1.33M EDGAR
2026-02-02 SNDK Notice (144) −2,000 -$1.33M EDGAR
2026-01-21 SNDK Notice (144) −2,000 -$984.6K EDGAR
2026-01-15 SNDK Notice (144) −1,000 -$421.5K EDGAR
2026-01-07 SNDK Notice (144) −2,000 -$693.8K EDGAR
2026-01-06 SNDK Notice (144) −2,816 -$953.0K EDGAR
Showing 1–10 of 123
Page 1 of 13
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.