SEC Form 4 · accession 0001366074-26-000002
Inhibrx Biosciences, Inc. · INBX
Statement of changes in beneficial ownership, as filed. Original on EDGAR ↗
Reporting owner
Mark Lappe
Officer — Chief Executive Officer · Director
Period of report
Sep 8, 2026
Accepted (ET)
Sep 8, 2026 · 4:04 pm EDT
Rule 10b5-1 plan
box not checked
Issuer CIK
0002007919
Table I — non-derivative securities
| Security | Date | Code | Shares | Price | A/D | Owned after | D/I | Nature of ownership |
|---|---|---|---|---|---|---|---|---|
| Common StockF1,F2 | Sep 8, 2026 | P | 5,895 | $99.2948 | A | 711,443 | I | By the Lappe Family Trust |
| Common StockF3,F2 | Sep 8, 2026 | P | 6,605 | $100.6388 | A | 718,048 | I | By the Lappe Family Trust |
| Common StockF4,F2 | Sep 8, 2026 | P | 1,100 | $107.1239 | A | 719,148 | I | By the Lappe Family Trust |
| Common StockF5,F2 | Sep 8, 2026 | P | 500 | $108.235 | A | 719,648 | I | By the Lappe Family Trust |
| Common StockF6,F2 | Sep 8, 2026 | P | 1,219 | $111.8805 | A | 720,867 | I | By the Lappe Family Trust |
| Common StockF7,F2 | Sep 8, 2026 | P | 9,681 | $112.2819 | A | 730,548 | I | By the Lappe Family Trust |
| Common StockF8 | holding | — | — | — | 165,000 | I | By Lappe Descendants' Trust | |
| Common Stock | holding | — | — | — | 54,865 | I | The Mark Paul Lappe Roth IRA |
Table II — derivative securities
No Table II lines on this filing.
Explanation of responses
- F1The shares were purchased in multiple transactions at prices ranging from $98.88 to $99.8316 inclusive. The reported price reflects the weighted-average purchase price. The reporting person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer full information regarding the number of shares and prices at which the transactions were effected.
- F2These securities are directly owned by the Lappe Family Trust. Mark P. Lappe is a trustee of the Lappe Family Trust and, in such capacity, may be deemed to indirectly beneficially own the securities owned by the Lappe Family Trust.
- F3The shares were purchased in multiple transactions at prices ranging from $100.095 to $100.99 inclusive. The reported price reflects the weighted-average purchase price. The reporting person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer full information regarding the number of shares and prices at which the transactions were effected.
- F4The shares were purchased in multiple transactions at prices ranging from $106.6225 to $107.57 inclusive. The reported price reflects the weighted-average purchase price. The reporting person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer full information regarding the number of shares and prices at which the transactions were effected.
- F5The shares were purchased in multiple transactions at prices ranging from $108.05 to $108.66 inclusive. The reported price reflects the weighted-average purchase price. The reporting person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer full information regarding the number of shares and prices at which the transactions were effected.
- F6The shares were purchased in multiple transactions at prices ranging from $111.15 to $112.07 inclusive. The reported price reflects the weighted-average purchase price. The reporting person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer full information regarding the number of shares and prices at which the transactions were effected.
- F7The shares were purchased in multiple transactions at prices ranging from $112.15 to $112.44 inclusive. The reported price reflects the weighted-average purchase price. The reporting person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer full information regarding the number of shares and prices at which the transactions were effected.
- F8These securities are directly owned by a trust, for the benefit of the reporting person's immediate family. Mark P. Lappe, as an immediate family member of the beneficiaries of the trust, may be deemed to indirectly beneficially own the securities owned by the trust.