Legence (LGN) said late Tuesday that stockholders affiliated with Blackstone (BX) plan to sell 7 million Class A shares in a secondary underwritten public offering.

They also plan to grant their underwriters a 30-day option to buy up to an additional 1.05 million shares, the firm said. Legence said it is not selling any shares in the offering.

Legence shares were down over 5% in after-hours activity.