Inhibrx director trust buys 5,000 INBX shares
Inhibrx Biosciences, Inc. (INBX) director Jon Faiz Kayyem reported an open-market purchase of 5,000 shares of common stock on September 16, 2026 at $100 per share, made indirectly through The Jon F. Kayyem and Paige Gates-Kayyem Family Trust.
Rhea-AI Filing Summary
Inhibrx Biosciences, Inc. (INBX) director Jon Faiz Kayyem reported an open-market purchase of 5,000 shares of common stock on September 16, 2026 at $100 per share, made indirectly through The Jon F. Kayyem and Paige Gates-Kayyem Family Trust. Following this transaction, that trust holds 429,360 shares. Additional indirect holdings reported include 250,000 shares held by the Jon Faiz Kayyem Revocable Trust, 250,000 shares held by the Paige Gates-Kayyem Revocable Trust, and 69,843 shares held in a custodial account for each of two minor children, for which the reporting person disclaims beneficial ownership in certain cases except to the extent of any indirect pecuniary interest.
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Insights
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Insider Trade Summary
Net Buyer: 5,000 shares
Net Buy
5 txns
Insider
Kayyem Jon Faiz
Role
Director
Bought
5,000 shs ($500K)
| Type | Security | Shares | Price | Value |
|---|---|---|---|---|
| Purchase | Common Stock F1 | 5,000 | $100.00 | $500K |
| holding | Common Stock F2 | -- | -- | -- |
| holding | Common Stock F3 | -- | -- | -- |
| holding | Common Stock F4 | -- | -- | -- |
| holding | Common Stock F5 | -- | -- | -- |
Holdings After Transaction:
Common Stock — 429,360 shares (Indirect, By The Jon F. Kayyem and Paige Gates-Kayyem Family Trust);
Common Stock — 250,000 shares (Indirect, By Jon Faiz Kayyem Revocable Trust);
Common Stock — 250,000 shares (Indirect, By Paige Gates-Kayyem Revocable Trust);
Common Stock — 69,843 shares (Indirect, By Child A);
Common Stock — 69,843 shares (Indirect, By Child B)
Footnotes (5)
- F1. These securities are directly owned by The Jon F. Kayyem and Paige Gates-Kayyem Family Trust. Jon Faiz Kayyem is the trustee of The Jon Faiz Kayyem and Paige N. Gates Family Trust and he disclaims beneficial ownership of these securities, except to the extent of any indirect pecuniary interest in his distributive shares therein.
- F2. These securities are directly owned by the Jon Faiz Kayyem Revocable Trust, of which Jon Faiz Kayyem is the trustee.
- F3. These securities are directly owned by the Paige-Gates Kayyem Revocable Trust, of which Jon Faiz Kayyem's spouse is the trustee.
- F4. These securities are directly owned by a custodial account managed by the reporting person for the benefit of the reporting person's minor child, Child A. The reporting person disclaims beneficial ownership of these securities, except to the extent of any indirect pecuniary interest in his distributive shares therein.
- F5. These securities are directly owned by a custodial account managed by the reporting person for the benefit of the reporting person's minor child, Child B. The reporting person disclaims beneficial ownership of these securities, except to the extent of any indirect pecuniary interest in his distributive shares therein.
Key Figures
Shares purchased: 5,000 shares of common stock
Purchase price per share: $100.00 per share
Family Trust holdings after transaction: 429,360 shares
+4 more
7 metrics
Shares purchased
5,000 shares of common stock
Indirect open-market or private purchase on September 16, 2026
Purchase price per share
$100.00 per share
Price for the 5,000-share purchase on September 16, 2026
Family Trust holdings after transaction
429,360 shares
Common stock held by The Jon F. Kayyem and Paige Gates-Kayyem Family Trust after the purchase
Jon Faiz Kayyem Revocable Trust holdings
250,000 shares
Common stock held indirectly via the Jon Faiz Kayyem Revocable Trust as of September 16, 2026
Paige Gates-Kayyem Revocable Trust holdings
250,000 shares
Common stock held indirectly via the Paige Gates-Kayyem Revocable Trust as of September 16, 2026
Child A custodial account holdings
69,843 shares
Common stock held in a custodial account for Child A, with certain beneficial ownership disclaimed
Child B custodial account holdings
69,843 shares
Common stock held in a custodial account for Child B, with certain beneficial ownership disclaimed
Key Terms
beneficial ownership, indirect pecuniary interest, Revocable Trust, custodial account
4 terms
beneficial ownership financial
"The reporting person disclaims beneficial ownership of these securities, except to the extent of any indirect pecuniary interest"
Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.
indirect pecuniary interest financial
"except to the extent of any indirect pecuniary interest in his distributive shares therein"
Revocable Trust financial
"These securities are directly owned by the Jon Faiz Kayyem Revocable Trust"
A revocable trust is a legal arrangement where the person who creates it keeps control and can change or cancel the trust at any time, while naming who will manage and receive the assets later. Think of it like a flexible folder for your investments and property that can be relabeled or reworked as circumstances change; it matters to investors because it determines how ownership is recorded, how easily assets transfer on incapacity or death, and whether holdings bypass public probate proceedings.
custodial account financial
"These securities are directly owned by a custodial account managed by the reporting person"
A custodial account is an investment or bank account opened and managed by an adult (the custodian) for the benefit of someone who cannot legally control assets, typically a minor. Think of it as a wallet held by a trusted guardian until the beneficiary reaches a legal age: it lets you save and invest on someone’s behalf, affects who makes decisions and who pays taxes, and determines when control of the assets transfers to the beneficiary—details investors watch for tax consequences, ownership rules, and timing of control.
FAQ
AI-generated questions and answers. How Rhea-AI works. Not financial advice.
What insider transaction did INBX director Jon Faiz Kayyem report?
He reported an indirect purchase of 5,000 shares of Inhibrx Biosciences common stock on September 16, 2026, executed through The Jon F. Kayyem and Paige Gates-Kayyem Family Trust.
What other indirect INBX holdings are reported for Jon Faiz Kayyem?
The Form 4 lists 250,000 shares held by the Jon Faiz Kayyem Revocable Trust, 250,000 shares held by the Paige Gates-Kayyem Revocable Trust, and 69,843 shares in a custodial account for each of two minor children.
Does this INBX Form 4 indicate trades under a Rule 10b5-1 trading plan?
No. The filing’s Rule 10b5-1 checkbox is not marked as an affirmative plan, and the footnotes do not state that the 5,000-share purchase or related holdings were made pursuant to a Rule 10b5-1 or similar pre-arranged trading plan.
How does Jon Faiz Kayyem describe his beneficial ownership of certain INBX holdings?
For shares held by the family trust and the custodial accounts for two minor children, the reporting person disclaims beneficial ownership except to the extent of any indirect pecuniary interest in his distributive shares, as stated in the footnotes.
AI-generated analysis. How Rhea-AI works. Not financial advice.
