Cambridge’s Sage Therapeutics has completed its initial public offering of stock, raising $90 million with the possibility of raising as much as $103.5 million.
The company sold shares at the top end of its proposed range, at $18 a piece.
The firm, which is developing a treatment for a life-threatening seizure condition, said last month in its initial filing with the US Securities and Exchange Commission that it sought to raise up $69 million, but ended up finding higher demand from investors.
The company sold 5 million shares, and could sell another 750,000 over-allotment shares to underwriters, leading to the higher total figure.
Shares are expected to begin trading on Friday.
The IPO is the 12th by a Massachusetts-based biotech firm so far in 2014, taking the state even farther past its prior record of nine, set last year. (Here’s the list of 11 previous local biotech IPOs this year.)
The offering follows a Series C venture round of $38 million raised by Sage Therapeutics in March.
Third Rock Ventures, a Boston life science venture firm, founded Sage in 2011. The startup has raised $93 million in funding to date.
Top shareholders in Sage Therapeutics include Third Rock (58.5 percent of shares), ARCH Venture Partners (21.3 percent of shares), and Fidelity Investments (5.6 percent of shares).
Sage’s initial treatment is an intravenous medicine for a seizure condition known as super refractory status epilepticus, which strikes 150,000 US patients each year and currently has no approved therapies. Sage recently opened enrollment for a Phase 1/2 clinical trial of the product candidate, SAGE-547.
The treatment is the lead program in a potential portfolio of seizure medicines, Sage has said. It will be followed by intravenous and oral compounds designed to treat patients with earlier-stage seizure disorders, along with other central nervous system disorders, according to the company.