Alumis (ALMS) said late Wednesday it priced an upsized underwritten public offering of 17.7 million common shares at $17 apiece to raise gross proceeds of about $300 million.

Alumis said it has granted the underwriters a 30-day option to buy up to an additional 2.6 million common shares at the same price.

The offering is expected to close on Friday, the company said.

Alumis' shares were down 1.2% in recent Thursday premarket activity.