Atlas Venture Fund X, L.P.

CIK 1628098 · last filed 2024-01-25

Atlas Venture Fund X, L.P. is a corporate insider who has filed 15 SEC Form 4 insider transactions across 6 companies since 2018. The most recent filing shows the insider sold $91.3M of IRON on Jan 25, 2024. Across all open-market trades the lifetime net is −$46.3M, making them a net seller over the disclosed history. Current disclosed insider exposure totals $662.1M 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.

Loading insider history…
Disclosed Exposure

$662.06M

Companies

6

Total Filings

15

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 $67.99 $143.18M -$91.33M 1 2024-01-25
Generation Bio Co. (GBIO) Delisted 10%+ Owner 8,278,876 $5.34 $44.21M $0 4 2021-09-21
KYMR 10%+ Owner 5,763,012 $86.20 $496.80M $0 2 2021-05-18
Dianthus Therapeutics, Inc. /DE/ (MGTA) Delisted 10%+ Owner 3,148,399 $11.19 $35.24M $0 2 2021-02-16
REPL 10%+ Owner 2,486,296 $8.88 $22.08M $0 4 2020-09-17
Tectonic Therapeutic, Inc. (AVRO) Delisted 10%+ Owner 4,756,478 $16.80 $79.91M $45.00M 2 2019-07-29

Recent Filings

15 filings
Form 4 transactions across all companies, newest first.
Filed Symbol Action Net Shares Net $ Link
2024-01-25 IRON Sell (S) −1,350,000 -$91.33M EDGAR
2021-09-21 Generation Bio Co. (GBIO) Delisted Other (J) −2,200,000 $0 EDGAR
2021-06-21 Generation Bio Co. (GBIO) Delisted Other (J) −2,200,000 $0 EDGAR
2021-05-18 KYMR Other (J) −1,122,619 $0 EDGAR
2021-03-18 Generation Bio Co. (GBIO) Delisted Other (J) −1,000,000 $0 EDGAR
2021-02-22 KYMR Other (J) −1,063,351 $0 EDGAR
2021-02-16 Dianthus Therapeutics, Inc. /DE/ (MGTA) Delisted Other (J) −968,726 $0 EDGAR
2020-12-17 Generation Bio Co. (GBIO) Delisted Other (J) −2,303,764 $0 EDGAR
2020-09-17 REPL Other (J) −445,339 $0 EDGAR
2020-07-07 REPL Other (J) −445,339 $0 EDGAR
Showing 110 of 15
Page 1 of 2
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.