Parabilis Medicines just pulled off one of the larger biotech IPOs of 2026, pricing 33.5 million shares at $20 each to raise $670 million in gross proceeds. That price landed above the company’s initial range of $17 to $19 per share, and the share count itself was upsized from a planned 25 million.
Shares are set to begin trading on Nasdaq under the ticker PBLS starting June 10, 2026.
The numbers behind the upsizing
Parabilis originally expected to sell 25 million shares in a range of $17 to $19. At the midpoint of that range, the company would have raised roughly $450 million. Instead, it raised $670 million, nearly 50% more than the midpoint scenario would have delivered.
The $670 million figure sets a new record for the largest biotech IPO by proceeds, surpassing the previous record held by Kailera Therapeutics at $625 million.
On top of the public offering, the company locked in a concurrent private placement with Regeneron Pharmaceuticals worth $75 million. Regeneron’s shares were priced at $18 each, a slight discount to the IPO price. Combined, Parabilis pulled in $745 million across both transactions.
What Parabilis actually does
Parabilis Medicines was founded in Cambridge, Massachusetts in 2015, starting operations in 2016, originally under the name Fog Pharmaceuticals before rebranding. The company’s core platform, called Helicon, comprises stabilized helical peptide therapeutics aimed at targeting complex intracellular protein interactions that traditional small molecules and antibodies have struggled to reach. In 2020, the company opened a 120,000-square-foot facility to support its pipeline development. The company is focused primarily on oncology and other serious diseases.
The company is still in the clinical stage, meaning its drug candidates are being tested in humans but none have been approved for sale yet. The $745 million raised through the IPO and Regeneron placement will need to fund clinical trials, regulatory work, and operations through what could be a long development timeline.