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David W Mason

CIK 1744907 · Chief Legal Officer · last filed 2026-04-28

David W Mason is a Chief Legal Officer who has filed 68 SEC Form 4 insider transactions across 2 companies since 2018. The most recent filing shows the insider disposed of $3.3M of SEMR on Apr 28, 2026. Across all open-market trades the lifetime net is −$5.6M, making them a net seller over the disclosed history. Current disclosed insider exposure totals $4.5M 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.

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Disclosed Exposure

$4.52M

Companies

2

Total Filings

68

Lifetime Open-Market Net

-$5.62M

Filer Profile

Reported Address
800 BOYLSTON STREET, SUITE 2475
BOSTON, MA 02199
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
SEMrush Holdings, Inc. (SEMR) Delisted Chief Legal Officer 0 $12.00 $0 -$1.50M 19 2026-04-28
EVER General Counsel and Secretary 192,509 $23.49 $4.52M -$4.12M 47 2022-10-05

Recent Filings

68 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
2026-04-28 SEMrush Holdings, Inc. (SEMR) Delisted Disp (D) −271,248 -$3.25M EDGAR
2026-03-09 SEMrush Holdings, Inc. (SEMR) Delisted Sell (S) −97,372 -$1.16M EDGAR
2026-03-05 SEMrush Holdings, Inc. (SEMR) Delisted Notice (144) −97,372 -$1.16M EDGAR
2025-12-17 SEMrush Holdings, Inc. (SEMR) Delisted Mixed +117,284 -$309.0K EDGAR
2025-12-02 SEMrush Holdings, Inc. (SEMR) Delisted Tax (F) −3,592 -$42.5K EDGAR
2025-11-03 SEMrush Holdings, Inc. (SEMR) Delisted Tax (F) −2,537 -$18.4K EDGAR
2025-09-02 SEMrush Holdings, Inc. (SEMR) Delisted Tax (F) −2,486 -$19.6K EDGAR
2025-08-04 SEMrush Holdings, Inc. (SEMR) Delisted Tax (F) −1,751 -$14.9K EDGAR
2025-06-04 SEMrush Holdings, Inc. (SEMR) Delisted Sell (S) −7,500 -$75.2K EDGAR
2025-06-03 SEMrush Holdings, Inc. (SEMR) Delisted Notice (144) −7,500 -$75.2K EDGAR
Showing 1–10 of 68
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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.