Spinoff Tracker

Every US corporate spin-off, sourced from the filing that proves it.

ANAPTYSBIO, INC ANAB → First Tracks Biotherapeutics, Inc. TRAX

Distribution2026-04-20
Return+131.77%
ParentANAPTYSBIO, INC ANAB
SpincoFirst Tracks Biotherapeutics, Inc. TRAX
StatusCompleted
StructureSpin-off A filing states a pro-rata distribution: holders receive shares automatically.
FocusFocus-increasing Parent and spinco operate in different industries — the class the research associates with stronger post-separation returns.
Ratio1 First Tracks share for every 1 AnaptysBio share
When-issued tickerTRAXV
Checked against EDGAR2026-08-21

Data trap

AnaptysBio retained only its royalty interests (GSK/Jemperli, Vanda/imsidolimab) and moved the entire drug-development pipeline to First Tracks. Any ANAB research-and-development or pipeline figure from before April 20, 2026 describes a company that no longer exists in that form. Screener share counts for TRAX were also unreliable until its first 10-Q on 2026-05-14, because a concurrent private placement issued shares on the distribution date itself.

The restated filings have landed; this is kept as history.

Catalyst clock

  1. 2025-09-29Separation announced
  2. 2026-03-03Form 10 filed
  3. 2026-03-27Form 10 last amended
  4. 2026-04-01Form 10 effective
  5. 2026-04-06Record date
  6. 2026-04-06When-issued trading opens
  7. 2026-04-20Distribution
  8. First standalone earnings
  9. Index inclusion announced

Performance since separation

First Tracks Biotherapeutics, Inc. since separation+131.77%
ANAPTYSBIO, INC over the same window+13.33%
S&P 500 (SPY) over the same window+8.04%
Russell 2000 (IWM) over the same window+8.15%
Excess over the S&P 500+123.73%
Excess over the Russell 2000+123.62%

Measured from the first regular-way close on or after the distribution — 2026-04-20 at 18.60 — to 2026-08-21 at 43.11. Window: 4 months. That is a short window. Treat it as a fact about these few weeks, not as evidence about how the separation turns out. 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.

Pre-distribution investor return

Parent, announcement to separation+190.14%
Combined (ANAPTYSBIO, INC + First Tracks Biotherapeutics, Inc.), pre-distribution to now+124.11%
Combined excess over the S&P 500+116.28%
Combined excess over the Russell 2000+115.34%

Combined treats a pre-spin holding as 1 First Tracks share for every 1 AnaptysBio share valued at the parent's last close before regular post-spin trading resumed — 2026-04-17 at 45.00 — against that same basket today. That baseline is a practical proxy, not an attempt to isolate exactly how much value the separation transferred: for a large parent and a small spinco, ordinary day-to-day price noise can be bigger than the transfer itself. Run-up measures only the parent's own price, from the announcement date to that same baseline — how far the market had already moved before the separation's mechanics ever happened.

Filings

Every fact on this page comes from one of these.

Notes

AnaptysBio separated its biopharma operations (rosnilimab, ANB033, ANB101), keeping the royalty-monetisation business behind. Explicitly TAXABLE to AnaptysBio holders for US federal income tax purposes — unusual for a spin-off and material to cost-basis questions. Classified focus-increasing: the parent became a royalty vehicle while the spinco carries the drug development, despite both legs sharing SIC 2834. EcoR1 funds bought First Tracks shares at a stated price on the distribution date; the May 2026 S-1 registers those shares for resale and is not a carve-out IPO.