Atlas Venture Opportunity Fund II, L.P.

CIK 1885327 · last filed 2025-02-10

Atlas Venture Opportunity Fund II, L.P. is a corporate insider who has filed 48 SEC Form 4 insider transactions across 2 companies since 2024. The most recent filing, for DYN, was dated Aug 14, 2026. Across all open-market trades the lifetime net is −$95.6M, making them a net seller over the disclosed history. Current disclosed insider exposure totals $219.2M 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

$219.22M

Companies

2

Total Filings

48

Lifetime Open-Market Net

-$95.58M

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
SION 10%+ Owner 3,694,020 $5.94 $21.94M $6.48M 1 2025-02-10
DYN 10%+ Owner 7,587,471 $26.00 $197.27M -$102.06M 1 2024-02-23

Recent Filings

48 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
2026-08-14 DYN Notice (144) −478,377 -$12.42M EDGAR
2026-08-13 DYN Notice (144) −94,415 -$2.47M EDGAR
2026-08-11 KRRO Notice (144) −368 -$5.0K EDGAR
2026-07-07 DYN Notice (144) −77,387 -$1.77M EDGAR
2026-07-06 DYN Notice (144) −127,182 -$2.93M EDGAR
2026-07-06 KRRO Notice (144) −8,506 -$119.1K EDGAR
2026-07-02 KRRO Notice (144) −14,745 -$201.3K EDGAR
2026-06-29 DYN Notice (144) −51,756 -$1.08M EDGAR
2026-06-26 DYN Notice (144) −81,903 -$1.69M EDGAR
2026-06-25 DYN Notice (144) −6,382 -$129.7K EDGAR
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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.