Third Rock Ventures GP III, L.P.

CIK 1637300 · last filed 2022-12-15

Third Rock Ventures GP III, L.P. is a corporate insider who has filed 8 SEC Form 4 insider transactions across 4 companies since 2017. The most recent filing, for FULC, was dated Dec 15, 2022. Across all open-market trades the lifetime net is −$14.9M, making them a net seller over the disclosed history. Current disclosed insider exposure totals $276.7M 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.

Disclosed Exposure

$276.72M

Companies

4

Total Filings

8

Lifetime Open-Market Net

-$14.90M

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
FULC	10%+ Owner	4,305,356	$3.67	$15.80M	$0	1	2022-12-15
PLRX	10%+ Owner	5,972,027	$1.14	$6.80M	$0	2	2022-09-22
VYGR	10%+ Owner	5,778,905	$3.79	$21.87M	-$14.90M	4	2022-08-18
RLAY	10%+ Owner	12,799,078	$18.14	$232.24M	$0	1	2020-07-21

Recent Filings

8 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
2022-12-15	FULC	Other (J)	−8,000,000	$0	EDGAR
2022-09-22	PLRX	Other (J)	−8,000,000	$0	EDGAR
2022-08-18	VYGR	Sell (S)	−513,824	-$3.10M	EDGAR
2022-08-16	VYGR	Sell (S)	−1,935,260	-$11.80M	EDGAR
2020-07-21	RLAY	Conv (C)	+115,191,702	$0	EDGAR
2020-06-09	PLRX	Conv (C)	+69,230,763	$0	EDGAR
2018-06-21	VYGR	Other (J)	−7,500,000	$0	EDGAR
2017-04-14	VYGR	Other (J)	−4,600,000	$0	EDGAR

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.