NioCorp Developments (NB) said Thursday it priced its underwritten public offering of about 7.7 million common shares at $2.60 per share for gross proceeds of about $20 million.

The company said it granted the underwriter a 30-day option to buy up to an additional 15% of the number of initial shares in the offering, which is expected to close on or about April 21.

The company's shares were over 12% lower in recent premarket activity.