Atlas Venture Fund X, L.P.

CIK 1628098 · last filed 2024-01-25

"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

$857.07M

Companies

6

Total Filings

65

Lifetime Open-Market Net

-$46.33M

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
IRON 10%+ Owner 2,105,846 $81.51 $171.65M -$91.33M 1 2024-01-25
Generation Bio Co. (GBIO) Delisted 10%+ Owner 827,888 $5.34 $4.42M $0 4 2021-09-21
KYMR 10%+ Owner 5,763,012 $112.26 $646.96M $0 2 2021-05-18
Dianthus Therapeutics, Inc. /DE/ (MGTA) Delisted 10%+ Owner 196,775 $11.19 $2.20M $0 2 2021-02-16
REPL 10%+ Owner 2,486,296 $15.47 $38.46M $0 4 2020-09-17
Tectonic Therapeutic, Inc. (AVRO) Delisted 10%+ Owner 396,373 $16.80 $6.66M $45.00M 2 2019-07-29

Recent Filings · Page 7 of 7

65 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
2020-06-18 REPL Other (J) −445,339 $0 EDGAR
2019-07-29 Tectonic Therapeutic, Inc. (AVRO) Delisted $0 EDGAR
2019-07-23 Tectonic Therapeutic, Inc. (AVRO) Delisted Buy (P) +2,432,433 $45.00M EDGAR
2019-02-14 REPL Other (J) −631,073 $0 EDGAR
2018-06-27 Dianthus Therapeutics, Inc. /DE/ (MGTA) Delisted Conv (C) +14,240,628 $0 EDGAR
Showing 6165 of 65
Page 7 of 7
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.