Parabilis Medicines, a clinical-stage biopharmaceutical company focused on developing therapies against historically undruggable protein targets, announced the closing of its upsized initial public offering and a concurrent private placement with Regeneron Pharmaceuticals.
The company sold 38.525 million shares of common stock, including the full exercise of the underwriters’ option to purchase an additional 5.025 million shares, at an initial public offering price of $20 per share. Parabilis shares began trading on the Nasdaq Global Select Market on June 10 under the ticker symbol “PBLS.”
The IPO generated gross proceeds of approximately $770.5 million before underwriting discounts, commissions, and offering expenses.
In addition, Parabilis completed a concurrent private placement with Regeneron Pharmaceuticals on June 11. Under the transaction, Regeneron purchased 4,166,666 shares at $18 per share, representing 90% of the IPO price. The private placement generated approximately $75 million in additional proceeds.
Combined, the transactions brought in roughly $845.5 million. The company noted that it has raised more than $1.2 billion in 2026 through a combination of public and private financings and strategic collaborations.
Parabilis also said that all outstanding preferred stock converted into common stock in connection with the offering, along with a $50 million Simple Agreement for Future Equity (SAFE) held by Explore Investments.
Founded in Cambridge, Massachusetts, Parabilis is developing a new therapeutic modality known as Helicons, stabilized helical peptides designed to precisely modulate proteins that have traditionally been inaccessible to conventional medicines.