ATLAS VENTURE ASSOCIATES X, L.P.
CIK 1742766 · last filed 2024-03-13
"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
$817.45M
Companies
6
Total Filings
12
Lifetime Open-Market Net
-$382.95M
Charts
Trading activity, where the exposure sits, and each trade against the stock price.
Filer Profile
Reported Address
400 TECHNOLOGY SQ.10TH FLOOR
CAMBRIDGE, MA 02139
Phone
(857) 201-2700
State of Incorporation
DE
Related Filers
Atlas Venture Associates X, LLC — 38 joint filings, latest 2026-02-09
Atlas Venture Fund X, L.P. — 29 joint filings, latest 2026-02-09
Atlas Venture Associates Opportunity I, LLC — 24 joint filings, latest 2026-02-09
Atlas Venture Opportunity Fund I, L.P. — 23 joint filings, latest 2026-02-09
Atlas Venture Associates Opportunity I, L.P. — 21 joint filings, latest 2026-02-09
Atlas Venture Fund XI, L.P. — 3 joint filings, latest 2021-05-26
Atlas Venture Associates Opportunity II, LLC — 2 joint filings, latest 2024-03-27
Atlas Venture Associates XI, L.P. — 2 joint filings, latest 2021-04-01
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 |
|---|---|---|---|---|---|---|---|
| KYMR | 10%+ Owner | 5,812,200 | $105.20 | $611.44M | -$184.55M | 5 | 2024-03-13 |
| IRON | 10%+ Owner | 2,347,367 | $63.57 | $149.22M | -$183.18M | 2 | 2023-12-14 |
| Generation Bio Co. (GBIO) Delisted | 10%+ Owner | 911,194 | $5.34 | $4.87M | -$14.46M | 2 | 2021-04-14 |
| Tectonic Therapeutic, Inc. (AVRO) Delisted | 10%+ Owner | 309,171 | $16.80 | $5.19M | $0 | 1 | 2020-02-18 |
| Dianthus Therapeutics, Inc. /DE/ (MGTA) Delisted | 10%+ Owner | 257,320 | $11.19 | $2.88M | -$763.2K | 1 | 2019-03-22 |
| REPL | 10%+ Owner | 4,453,386 | $12.75 | $56.78M | $0 | 1 | 2018-07-26 |
Recent Filings · Page 2 of 2
12 filingsInsider 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 |
|---|---|---|---|---|---|
| 2019-03-22 | Dianthus Therapeutics, Inc. /DE/ (MGTA) Delisted | Mixed | −2,179,500 | -$763.2K | EDGAR |
| 2018-07-26 | REPL | Conv (C) | +13,360,158 | $0 | EDGAR |
Showing 11–12 of 12
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Page 2 of 2
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.
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.