According to the press release, the transaction would create two independent companies:
- A royalty management company, holding tiered royalties on GSK’s Jemperli and milestone/royalty potential from Vanda’s imsidolimab.
- A biopharma company, advancing Anaptys’s clinical pipeline, including rosnilimab (anti-PD-1 agonist), ANB033 (anti-CD122 antagonist), and ANB101 (BDCA2 modulator).
Unusually, the company currently expects the separation to be taxable and says it is working to minimize the impact at both the corporate and shareholder levels. The board has approved the plan in principle, with execution targeted by year-end 2026.
Why the AnaptysBio Stock Popped
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Investors get two cleaner stories: a royalty engine and a growth biotech.
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Royalty Co’s predictable income is easier to model and value on cash flows.
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Biopharma Co keeps the high-risk/high-reward pipeline separate, appealing to different investor bases.
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Analysts are reacting fast — H.C. Wainwright raised its ANAB target to $59 after the announcement.
AnaptysBio Spinoff: What Could the Two Companies Be Worth?
After yesterday’s rally, ANAB sits around $32/share, up over 30% on the spin announcement. That implies a ~$900M market cap. What does a sum of the parts valuation look like?
Royalty Management Co: Cash Flow Play
The “royalty company” will own rights to GSK’s Jemperli (dostarlimab) and Vanda’s imsidolimab.
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Jemperli royalties: tiered at 8% below $1B in sales, rising to 12–25% above $1B.
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AnaptysBio already monetized part of the stream through Sagard for $250M upfront plus a $50M follow-on. Sagard collects until caps are reached (~$600M by 2031), after which full royalties revert to Anaptys.
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In Q1 2025, royalties lifted collaboration revenue to $27.8M, up from $7.2M the year before.
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AnaptysBio reported $383M in cash and investments as of March 31, 2025. Much or all of this will likely go to BioPharma to fund development
Royalty Co will be lower risk, lower burn, and attractive to investors looking for steady cash flow. The flip side: upside is capped until Sagard is paid off, and everything hinges on Jemperli’s growth trajectory.
Assumptions:
- Jemperli global sales reach $2B by 2030 (GSK guidance is aggressive on immuno-oncology uptake).
- Sagard monetization absorbs first ~$600M in royalties, reverting full rights by ~2028.
Valuation Sketch:
- Near-term royalties: ~$30–40M/year growing into low hundreds if Jemperli scales.
- near-term royalty DCF supports ~$100–200M equity value today.
- That’s $3–6/share out of the current $32 stock.
AnaptysBio Spinoff Biopharma Co: Pipeline and Upside
The “biopharma company” will hold AnaptysBio’s drug pipeline:
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Rosnilimab: lead PD-1 agonist program, with Phase 2b RA trial complete and Phase 2 UC readout due late 2025.
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ANB033: CD122 antagonist, in Phase 1b for celiac disease.
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ANB101: BDCA2 modulator, still early-stage.
The Biopharma Co. should get the bulk of the cash as well since the royalty business will not require material cash to operate.Here lies the burn and the binary risk of clinical trials, but also the possibility of biotech-style upside if rosnilimab or its siblings hit. The company has signaled openness to partnerships on rosnilimab.
Assumptions:
- Probability-adjusted NPV for rosnilimab in UC/RA: $300–500M.
- Early-stage assets add another ~$100M optionality.
- Burn rate funded by current cash reserves.
Valuation Sketch:
- Pipeline value could justify ~$400–600M equity value.
- $350M in cash
- That’s $28–34/share of current value, with upside if data hits.
AnaptysBio Sum Of The Parts Valuation
| Company | Est. Value Range | Per-Share Value |
|---|---|---|
| Royalty Management Co | $400–500M | $3–6/share |
| Biopharma Co | $400–600M | $28–34/share |
| Combined | $800–1.1B | $31–40/share |
AnaptysBio is Now Fairly Valued
The market at ~$32/share is pricing both pieces roughly in line with these sketches — but if Jemperli accelerates, or if rosnilimab delivers strong UC data next year, either side could re-rate sharply higher. Conversely, royalty monetization caps and biotech risk cut both ways.
This is the type of breakup where each side has a natural investor base: royalty investors chasing predictable cash, and biotech specialists chasing trial catalysts. Post-split, expect the market to assign higher multiples to each than to the blended entity today.
AnaptysBio Spinoff- What’s Next?
- Transaction structure and taxes — the separation is intended to be taxable, but the exact mechanics will matter a lot for holders.
- Timeline specifics — investors should watch for the eventual record date and distribution date once the split nears execution.
- Partnership strategy — the company signaled openness to partnering rosnilimab, which could affect valuation and funding needs.
Disclosure: The author holds no position in ANAB at publication.