Inhibrx, Inc. → Inhibrx Biosciences, Inc. INBX
| Parent | Inhibrx, Inc. |
|---|---|
| Spinco | Inhibrx Biosciences, Inc. INBX |
| Status | Completed |
| Structure | Spin-off A filing states a pro-rata distribution: holders receive shares automatically. |
| Focus | Not focus-increasing Parent and spinco remain in the same industry; the separation divides scale rather than business. |
| Ratio | 1 Inhibrx Biosciences share for every 4 Inhibrx shares |
| Ratio note | Distributed the day before Sanofi acquired the remaining parent for cash plus a contingent value right. |
| Parent retains | 8% |
| Checked against EDGAR | 2026-08-22 |
Data trap
The spinco did not trade under its present symbol at separation. It listed temporarily as INXB and only took the INBX symbol from the acquired parent after the merger closed; no filing states the exact changeover date, so a price series keyed on INBX may not reach back to day zero. The parent's retained 8 percent passed to Sanofi's subsidiary the next day rather than being sold down. And the deal is accounted for as a REVERSE spin-off, so the spinco's pre-separation financial statements are the former parent's historicals, not a carve-out of a subsidiary.
The restated filings have landed; this is kept as history.
Catalyst clock
- 2024-01-23Separation announced
- 2024-04-25Form 10 filed
- 2024-05-15Form 10 last amended
- 2024-05-24Form 10 effective
- 2024-05-17Record date
- —When-issued trading opens
- 2024-05-29Distribution
- 2024-08-13First standalone earnings
- —Index inclusion announced
Performance since separation
| Inhibrx Biosciences, Inc. since separation | +203.81% |
|---|---|
| Inhibrx, Inc. over the same window | never listed separately |
| S&P 500 (SPY) over the same window | +45.55% |
| Russell 2000 (IWM) over the same window | +48.40% |
| Excess over the S&P 500 | +158.26% |
| Excess over the Russell 2000 | +155.41% |
Measured from the first regular-way close on or after the distribution — 2024-05-29 at 34.11 — to 2026-08-21 at 103.63. Window: 2.2 years. Two benchmarks, because one is misleading: spin-offs are usually small companies, and across this period small caps lagged the S&P by several points a year on their own. Measured against the S&P alone, roughly a third of any shortfall is company size rather than the separation. Returns are arithmetic over end-of-day closing prices. Unlike every other figure on this page, they do not come from a filing.
Filings
Every fact on this page comes from one of these.
- 8-Kfiled 2024-01-23 · 0001104659-24-005727Merger agreement with a Sanofi subsidiary and the separation agreement, both dated January 22, 2024
- 10-12B/Afiled 2024-05-15 · 0001104659-24-061562Final Form 10 amendment; its Ex-99.1 is only the preliminary information statement
- 8-Kfiled 2024-05-24 · 0001104659-24-065140Form 10 declared effective; definitive information statement with the 1-for-4 ratio, the May 17 record date and the 92/8 split
- 8-Kfiled 2024-05-30 · 0001104659-24-066645Completion: 92 percent distributed effective 11:59 p.m. on May 29, 2024; 14,475,904 shares outstanding
- 10-Qfiled 2024-08-13 · 0002007919-24-000029First periodic report; reverse-spin-off accounting under ASC 505-60
Notes
Inhibrx separated its clinical pipeline into a new company one day before Sanofi acquired the remainder for 30 dollars a share plus a contingent value right. Holders received the spinco shares automatically and separately from the merger consideration, which is what makes this a genuine distribution rather than part of the merger price. Left unclassified: parent and spinco share a biotechnology SIC code and the separation was driven by the acquisition rather than by focus. Classified non_focus_increasing: the Form 10 frames this as a program-level carve-out inside one continuous biologics platform, not an industry split — RemainCo keeps only INBRX-101 (destined for the Sanofi acquisition) while SpinCo keeps the broader pipeline (INBRX-105/106/109) and the Inhibrx name, both still built on the same protein-engineering platform. The separation exists to structure the Sanofi sale tax-efficiently, not to sharpen either company's strategic focus — the 'Reasons for the Distribution' section says so explicitly.