Lyell Immunopharma LYEL Insider Ownership

NASDAQ LYEL

$9.38 -0.03 (-0.32%)

At close: Oct 22, 2026 · 4:00 PM EDT

Insider Holdings by Owner

6.09Mn Shares

Insider Ownership Statistics

as of 30 Sep, 2026

Insider Ownership

26.81%

▼-0.325% pp QoQ

Shares Held by Insiders

6.27Mn

filed for Sep 2026

▼-1.20% QoQ

Shares Outstanding

23.40Mn

23,397,000 shares

Direct Holdings

2.95Mn

Indirect: 3.32Mn

Net Shares Traded (QoQ)

-76.01K

net selling in Sep 2026

Insiders Holding Shares

with Form 4 holdings on file

Shares Owned by Insiders

Shares held % of outstanding

Latest —

Average ownership —

Peak ownership —

Shares Purchased/Sold by Insiders

Bought Sold

Latest quarter —

Net over range —

Buying quarters —

Insider Ownership Summary

Updated Oct 16, 2026

Over the trailing 12 months, LYEL insiders bought $12.5 million worth of shares (488.09K shares) and sold $608,228 worth (31.27K shares) in open-market trades.

By number of insiders, Lyell Immunopharma saw one insider buy and 7 insiders sell on the open market over the past 12 months.
Among Lyell Immunopharma's insiders, the largest open-market purchases in the past 12 months were by Arch Venture Fund XIII, L.P. (10% owner), totaling $12.5 million (488.09K shares), most recently on March 6, 2026.
Conversely, Lynn Seely (President and CEO) was LYEL's largest open-market seller in the past 12 months, with $353,079 of sales (18.67K shares); the latest was on August 21, 2026.
Lyell Immunopharma's latest insider trade on the open market was a sale of 422 shares for $3,642 by Jarrad Mattieu Aguirre (Chief Medical Officer) on October 12, 2026.
Beyond open-market trades, insiders at Lyell Immunopharma received 32.75K shares in stock awards in the last 12 months.
Business Quant data shows Lyell Immunopharma insiders holding 6.27Mn shares in total in their latest Form 4 filings, down 1.20% from 6.35Mn shares at the end of Q2 2026.
By type of ownership, LYEL insiders hold 47.06% of their shares directly (2.95Mn shares) and 52.94% indirectly (3.32Mn shares).
The insider holdings in Lyell Immunopharma belong to 14 insiders who have reported on Form 4 within the past two years.
Lyell Immunopharma's top three insider holders by shares held are Arch Venture Partners IX, LLC (10% owner, 3.25Mn shares), Innovative Cellular Therapeutics Holdings Ltd (10% owner, 2.77Mn shares) and Lynn Seely (President and CEO, 63.9K shares).
Arch Venture Partners IX, LLC holds 51.76% of the combined insider position in Lyell Immunopharma.
Institutional holders reported 54.17% of Lyell Immunopharma's outstanding shares for Q2 2026; insiders' latest Form 4 filings put their stake at about 26.81%, and other investors, including the public, hold the remaining 19.02%.
Over the past 12 months, 17 insiders reported transactions in Lyell Immunopharma stock in 47 Form 4 filings.
This summary of Lyell Immunopharma insider activity covers Form 4 filings through October 13, 2026.

Form 4 Holdings

Insiders Holding LYEL

Insiders 15

Shares held 6.09Mn

Of outstanding 26.04%

#	Insider	Position	Direct	Indirect	Total	Share of Insiders	Last Filed
1	Cellular Therapeutics Holdings Ltd Innovative	TenPercentOwner	2,774,980	0	2,774,980	45.6%	27 Jul, 2026
2	Venture Fund Xiii, L.P. Arch	TenPercentOwner	0	1,426,528	1,426,528	23.4%	09 Mar, 2026
3	Venture Partners Ix, Llc Arch	TenPercentOwner	0	1,426,528	1,426,528	23.4%	09 Mar, 2026
4	Hans Edgar Bishop	Director	234,281	0	234,281	3.8%	09 Sep, 2022
5	Lynn Seely	President And Ceo	63,899	0	63,899	1.0%	25 Aug, 2026
6	Richard Klausner	Director	0	42,168	42,168	0.7%	18 Mar, 2025
7	David Shook	Chief Medical Officer	20,423	0	20,423	0.3%	10 Sep, 2026
8	Jarrad Mattieu Aguirre	Chief Medical Officer	19,857	0	19,857	0.3%	13 Oct, 2026
9	Stephen J. Hill	Chief Operating Officer	16,816	0	16,816	0.3%	25 Aug, 2026
10	Gary K. Lee	Chief Scientific Officer	16,220	0	16,220	0.3%	25 Aug, 2026
11	Charles W. Newton	Chief Financial Officer	15,306	0	15,306	0.3%	22 Aug, 2025
12	Veronica Sanchez Bulis	Vp, Corporate Controller	14,799	0	14,799	0.2%	11 Aug, 2026
13	Sumant Ramachandra	Director	0	10,000	10,000	0.2%	25 Mar, 2025
14	Matthew Lang	Chief Business Officer	8,125	0	8,125	0.1%	26 Feb, 2025
15	Otis W Brawley	Director	1,782	0	1,782	0.0%	02 Apr, 2025

Each row is that insider’s most recently reported position, from Form 4 filings over the last 60 months — which is why this total does not tie to the quarterly series above, where a quarter counts only the insiders who filed in it. Shares held through a fund or institutional portfolio are counted on the institutional ownership page instead.

Form 4 Filings

205 Insider Transactions

Source SEC Form 4

Latest quarter Sep 2026

Date	Insider	Position	Transaction	Shares	Price	Value	Shares Held After	Ownership
12 Oct, 2026	Jarrad Mattieu Aguirre	Chief Medical Officer	Disposed S	422	$8.63	$3.64K	19,857	Direct
10 Sep, 2026	David Shook	Chief Medical Officer	Disposed S	500	$12.70	$6.35K	20,423	Direct
10 Sep, 2026	Jarrad Mattieu Aguirre	Chief Medical Officer	Acquired A	47,500	$0.00	$0	47,500	Direct
21 Aug, 2026	Lynn Seely	President And Ceo	Disposed S	9,589	$15.54	$149.01K	63,899	Direct
21 Aug, 2026	Stephen J. Hill	Chief Operating Officer	Disposed S	989	$15.54	$15.37K	16,816	Direct
21 Aug, 2026	Gary K. Lee	Chief Scientific Officer	Disposed S	1,457	$15.54	$22.64K	16,220	Direct
10 Aug, 2026	Stephen J. Hill	Chief Operating Officer	Disposed S	89	$14.34	$1.28K	17,805	Direct
10 Aug, 2026	Lynn Seely	President And Ceo	Disposed S	390	$14.34	$5.59K	73,488	Direct
10 Aug, 2026	Veronica Sanchez Bulis	Vp, Corporate Controller	Disposed S	621	$14.34	$8.91K	14,799	Direct
10 Aug, 2026	Gary K. Lee	Chief Scientific Officer	Disposed S	131	$14.34	$1.88K	17,677	Direct
27 Jul, 2026	Cellular Therapeutics Holdings Ltd Innovative	TenPercentOwner	Disposed J	38,500	$0.00	$0	2,818,980	Direct
27 Jul, 2026	Cellular Therapeutics Holdings Ltd Innovative	TenPercentOwner	Disposed J	44,000	$0.00	$0	2,774,980	Direct
17 Jul, 2026	Cellular Therapeutics Holdings Ltd Innovative	TenPercentOwner	Disposed S	10	$13.70	$137	2,857,480	Direct
16 Jul, 2026	Cellular Therapeutics Holdings Ltd Innovative	TenPercentOwner	Disposed S	10	$13.73	$137	2,857,490	Direct
29 Jun, 2026	Cellular Therapeutics Holdings Ltd Innovative	TenPercentOwner	Disposed J	76,000	$0.00	$0	2,857,500	Direct
15 Jun, 2026	Cellular Therapeutics Holdings Ltd Innovative	TenPercentOwner	Disposed J	66,500	$0.00	$0	2,933,500	Direct
11 May, 2026	Lynn Seely	President And Ceo	Disposed S	388	$18.91	$7.34K	73,878	Direct
11 May, 2026	Gary K. Lee	Chief Scientific Officer	Disposed S	130	$18.92	$2.46K	17,808	Direct
11 May, 2026	Stephen J. Hill	Chief Operating Officer	Disposed S	89	$18.92	$1.68K	17,894	Direct
11 May, 2026	Veronica Sanchez Bulis	Vp, Corporate Controller	Disposed S	217	$18.91	$4.10K	15,420	Direct

Showing 1 to 20 of 205 transactions