Inhibrx Biosciences, Inc. Insider Trading

INBX

Cluster buy

3 insiders bought $5.5M of their own stock in 21 days.

Open-market purchases by executives and directors between Sep 8 and Sep 28. Buying is rarer than selling and says more, but it is one input, not a verdict.

Net open-market

+$6.07M

7 buys · 2 sales

Under a 10b5-1 plan

of the value sold

Insiders who bought / sold

3 / 1

executives and directors

Last open-market buy

Oct 2026

Oct 14, 2026

Get an email when INBX's executives or directors buy, or make a large sale outside a plan.

Trades · last 2 years

Date	Insider	Trade	Shares	Price	Value	Of their stake	Filing
Oct 14	Mark Lappe Chief Executive Officer	Bought 6 parts	10,040	$84.56 average	849K	1.0%	Form 4
Sep 25 – 28	Mark Lappe Chief Executive Officer	Bought 4 parts	10,000	$99.88 average	999K	1.1%	Form 4
Sep 23	Jon Faiz Kayyem Director	Bought	5,000	$100.00	500K	0.5%	Form 4
Sep 16	Jon Faiz Kayyem Director	Bought	5,000	$100.00	500K	0.5%	Form 4
Sep 11 – 15	Kimberly Manhard Director	SoldNo plan 3 parts	1,500	$109.03 average	164K	17%	Form 4
Sep 8 – 9	Kimberly Manhard Director	SoldNo plan 2 parts	1,000	$115.47 average	115K	10%	Form 4
Sep 8	Jon Faiz Kayyem Director	Bought	5,000	$113.52	568K	0.5%	Form 4
Sep 8	Mark Lappe Chief Executive Officer	Bought 6 parts	25,000	$105.81 average	$2.65M	2.7%	Form 4
Sep 8	Douglas Forsyth Director	Bought	2,500	$114.65	287K	1.1%	Form 4
Oct 7, 2025	Viking Global Opportunities Parent GP LLC Large holder	SoldNo plan 3 parts	350,000	$32.25 average	$11.3M	77%	Form 4
Nov 19, 2024 – Nov 20, 2024	Jon Faiz Kayyem Director	Bought 4 parts	107,186	$14.22 average	$1.52M	330%	Form 4

Oct 14
Mark Lappe
Chief Executive Officer · bought 10,040 at avg $84.56
849K
1.0% of stake
Sep 25 – 28
Mark Lappe
Chief Executive Officer · bought 10,000 at avg $99.88
999K
1.1% of stake
Sep 23
Jon Faiz Kayyem
Director · bought 5,000 at $100.00
500K
0.5% of stake
Sep 16
Jon Faiz Kayyem
Director · bought 5,000 at $100.00
500K
0.5% of stake
Sep 11 – 15No plan
Kimberly Manhard
Director · sold 1,500 at avg $109.03
164K
17% of stake
Sep 8 – 9No plan
Kimberly Manhard
Director · sold 1,000 at avg $115.47
115K
10% of stake
Sep 8
Jon Faiz Kayyem
Director · bought 5,000 at $113.52
568K
0.5% of stake
Sep 8
Mark Lappe
Chief Executive Officer · bought 25,000 at avg $105.81
$2.65M
2.7% of stake
Sep 8
Douglas Forsyth
Director · bought 2,500 at $114.65
287K
1.1% of stake
Oct 7, 2025No plan
Viking Global Opportunities Parent GP LLC
Large holder · sold 350,000 at avg $32.25
$11.3M
77% of stake
Nov 19, 2024 – Nov 20, 2024
Jon Faiz Kayyem
Director · bought 107,186 at avg $14.22
$1.52M
330% of stake

How to read this. Insiders sell for many reasons: taxes, diversifying, a house. Open-market buys are rarer and say more. A 10b5-1 plan is a trading schedule set up months in advance, so those sales were not timed on news. Large holders (funds and 10% owners) are listed under Everything but not counted as insiders. If you own or watch INBX, we send a push when an executive buys or makes a large sale outside a plan.

Source: SEC Form 4 filings, filed within two business days of each trade and checked for new ones every hour.

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Held by ETFs

INBX is in 32 US ETFs. The largest of them, with INBX's weight in each:

Spot a number that looks wrong? Check it in INBX's SEC filings or

Download this analysis as a PDF (Pro)

Data sourced from SEC EDGAR filings and third-party price providers. Scores, valuations, and metrics are algorithmic estimates. This is not investment advice. See our Terms and Methodology.

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