ARCH Venture Partners IX, LLC

CIK 1723174 · last filed 2026-03-09

ARCH Venture Partners IX, LLC is a corporate insider who has filed 7 SEC Form 4 insider transactions across 4 companies since 2019. The most recent filing shows the insider bought $62.5M of LYEL on Mar 9, 2026. Across all open-market trades the lifetime net is +$62.5M, making them a net buyer over the disclosed history. Current disclosed insider exposure totals $207.2M 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.

Disclosed Exposure

$207.21M

Companies

4

Total Filings

7

Lifetime Open-Market Net

$62.50M

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
LYEL	10%+ Owner	910,317	$13.16	$11.98M	$62.50M	1	2026-03-09
VIR	10%+ Owner	11,735,405	$8.86	$103.98M	$0	2	2021-12-01
BEAM	10%+ Owner	3,523,953	$25.70	$90.57M	$0	3	2021-04-02
GOSS	10%+ Owner	4,027,958	$0.17	$689.6K	$0	1	2019-02-12

Recent Filings

7 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
2026-03-09	LYEL	Buy (P)	+2,440,450	$62.50M	EDGAR
2021-12-01	VIR	Other (J)	−3,377,605	$0	EDGAR
2021-04-09	VIR	Other (J)	−6,941,480	$0	EDGAR
2021-04-02	BEAM	Other (J)	−2,776,438	$0	EDGAR
2021-03-22	BEAM	Other (J)	−5,552,883	$0	EDGAR
2020-02-11	BEAM	Conv (C)	+57,701,273	$0	EDGAR
2019-02-12	GOSS	Conv (C)	+64,447,328	$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.