Here are the Form 4 insider transactions from Inhibrx Biosciences, Inc. (INBX) in our archive over the last 12 months, newest first, and each one links through to the document itself with the summary and the scores our analysis gives it.
A Form 4 covers the transactions officers, directors and large holders report, so if you follow INBX and want that one kind of document rather than the whole filing history, this is the page to keep. The company's other filings, of every form, are on the full INBX filings page.
Inhibrx Biosciences, Inc. Chief Executive Officer Mark Lappe reported that the Lappe Family Trust and Lappe Descendants’ Trust purchased 10,040 shares of common stock on October 14, 2026. The Family Trust purchased 2,470 shares at a weighted-average price of $84.0707 and another 2,470 at $84.9992, plus 100 shares at $85.7600. The Descendants’ Trust purchased 2,449 shares at $84.0707, 2,451 at $84.9992, and 100 at $85.7600. Lappe may be deemed to indirectly beneficially own the trust-held shares. No Rule 10b5-1 plan is reported.
Inhibrx Biosciences, Inc. (INBX) CEO and director Mark P. Lappe reported that the Lappe Family Trust, of which he is a trustee, purchased 10,000 common shares on September 25 and 28, 2026. The four weighted-average prices were $98.8659 (3,324 shares), $99.5988 (2,176), $98.8803 (1,500) and $101.7020 (3,000). No Rule 10b5-1 plan is reported. Separately listed indirect holdings as of September 25, 2026, were 165,000 shares in Lappe Descendants' Trust and 54,865 in the Mark Paul Lappe Roth IRA.
The Jon F. Kayyem and Paige Gates-Kayyem Family Trust purchased 5,000 common shares of Inhibrx Biosciences, Inc. (INBX) at $100 per share on September 23, 2026, bringing its reported holdings to 434,360 shares. Director Jon Faiz Kayyem disclaims beneficial ownership of the trust shares except to the extent of any indirect pecuniary interest in his distributive shares.
Other listed indirect positions included 250,000 shares in each of the Jon Faiz Kayyem Revocable Trust and Paige Gates-Kayyem Revocable Trust, and 69,843 shares in each custodial account for Child A and Child B. Kayyem disclaims beneficial ownership of the children's account shares except to the extent of any indirect pecuniary interest in his distributive shares.
Inhibrx Biosciences, Inc. (INBX) reports that director Douglas Forsyth received a grant of 10,000 stock options on June 3, 2026, as corrected in this amended Form 4. The options have an exercise price of $95.22 per share and cover 10,000 shares of common stock.
The options become fully exercisable on June 3, 2027, subject to Mr. Forsyth’s continued service through that date, and expire on June 3, 2036. Following this grant, Mr. Forsyth holds 10,000 options directly. No Rule 10b5-1 trading plan is reported in connection with this grant.
Inhibrx Biosciences, Inc. (INBX) reports that director Kristiina Vuori, MD received a grant of 10,000 stock options on June 3, 2026, each with an exercise price of $95.22 and expiring on June 3, 2036. The option becomes fully exercisable on June 3, 2027, subject to her continued service, and this amended filing corrects the original option amount reported.
Inhibrx Biosciences, Inc. reported that director Kimberly Manhard received a grant of 10,000 stock options on June 3, 2026. The options have an exercise price of $95.22 per share, become fully exercisable on June 3, 2027 subject to continued service, and expire on June 3, 2036. This amended report corrects the number of options originally disclosed and shows Manhard holding 10,000 options after the grant; the filing states the transactions were not made under a Rule 10b5-1 trading plan.
Inhibrx Biosciences, Inc. (INBX) reports that director Jon Faiz Kayyem received a corrected grant of 10,000 stock options on June 3, 2026, at an exercise price of $95.22 per share. These options become fully exercisable on June 3, 2027, and expire on June 3, 2036, with 10,000 options held directly after the grant. The amended Form 4 restates a prior filing to correct the number of options granted, and no Rule 10b5-1 trading plan is reported.
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.
Inhibrx Biosciences, Inc. (INBX) reported that director Kimberly Manhard, through the Kimberly Joan Manhard Revocable Trust dated June 4, 2012, sold a total of 1,500 shares of common stock in open market or private transactions on September 11, 14, and 15, 2026 at prices between $105.05 and $111.78 per share. The sales were reported as indirect ownership transactions by the trust, for which Ms. Manhard may be deemed to beneficially own the securities as trustee.
Inhibrx Biosciences, Inc. (INBX) director Kimberly Manhard reported indirect sales of common stock held by the Kimberly Joan Manhard Revocable Trust, Dtd 6/4/2012. The trust sold 500 shares on September 8, 2026 at $115.14 per share and 500 shares on September 9, 2026 at $115.795 per share. Manhard, as trustee, may be deemed to indirectly beneficially own the trust’s shares, and no Rule 10b5-1 trading plan is reported.
Inhibrx Biosciences, Inc. (INBX) director Jon Faiz Kayyem reported that The Jon F. Kayyem and Paige Gates-Kayyem Family Trust purchased 5,000 shares of common stock on September 8, 2026 at a weighted-average price of $113.52 per share in open-market transactions, with prices ranging from $113.30 to $113.55.
After this purchase, that Family Trust held 424,360 shares indirectly attributed to Kayyem, for which he disclaims beneficial ownership except for any indirect pecuniary interest. Additional indirect holdings reported include 250,000 shares in the Jon Faiz Kayyem Revocable Trust, 250,000 shares in the Paige Gates-Kayyem Revocable Trust, and 69,843 shares in custodial accounts for each of two minor children.
Inhibrx Biosciences, Inc. (INBX) director Douglas Forsyth reported an open-market purchase of company stock through a family trust. On September 8, 2026, the Forsyth Family Trust bought 2,500 shares of common stock at a weighted-average price of $114.6469 per share.
The shares are held indirectly via the Forsyth Family Trust Dated July 20, 2001, of which Forsyth is a trustee and may be deemed to indirectly beneficially own the securities. Following this transaction, the trust held 227,064 shares of Inhibrx Biosciences common stock. The price reflects multiple trades between $114.36 and $114.689 per share, and no Rule 10b5-1 trading plan is reported.
Inhibrx Biosciences, Inc. (INBX) reported that Chief Executive Officer and director Mark P. Lappe, through the Lappe Family Trust, purchased a total of 25,000 shares of common stock on September 8, 2026 in multiple open-market transactions at weighted-average prices around $99–$112 per share. The filing also reports additional indirect holdings in a family trust and a Roth IRA.
Inhibrx Biosciences director Kristiina Vuori, MD, received a grant of stock options for 15,000 shares of common stock. The options have an exercise price of $95.22 per share, become fully exercisable on June 3, 2027, subject to her continued service, and expire on June 3, 2036.
Inhibrx Biosciences, Inc. director Jon Faiz Kayyem received a grant of stock options covering 15,000 shares of common stock. The options have an exercise price of $95.2200 per share and become fully exercisable on June 3, 2027, subject to his continued service.
The options expire on June 3, 2036. Following this award, Kayyem holds 15,000 derivative securities (stock options) directly. This is a compensation-related grant, not an open‑market purchase or sale of shares.
Inhibrx Biosciences, Inc. director Douglas Forsyth received a grant of stock options covering 15,000 shares of Common Stock. The options have an exercise price of $95.22 per share and expire on June 3, 2036.
According to the filing, the stock option will become fully exercisable on June 3, 2027, subject to Forsyth’s continued service through that date. Following this award, he holds 15,000 stock options directly, and the transaction reflects compensation rather than an open‑market purchase or sale.
Inhibrx Biosciences, Inc. director Kimberly Manhard received a grant of stock options covering 15,000 shares of common stock. The options carry an exercise price of $95.22 per share and will be fully exercisable on June 3, 2027, subject to her continued service through that date.
Following this grant, she holds stock options for 15,000 underlying shares directly. This award is compensation-related and was not an open-market purchase or sale of existing shares.
Inhibrx Biosciences, Inc. reported that President David Matly received a grant of stock options covering 50,000 shares of common stock. The options have an exercise price of $129.06 per share and expire on April 24, 2036.
According to the vesting terms, 25% of the options become exercisable on April 24, 2027, with the remaining shares vesting in equal monthly installments over the next 36 months, subject to his continuous service with the company. Following this award, he holds 50,000 stock options directly.