Twitter is losing two more senior executives: The company’s head of media and commerce Nathan Hubbard is departing to found his own startup. Also on the way out is Jana Messerschmidt, Twitter’s head of biz dev. The departures were first reported by Recode Thursday, and have since been confirmed by Twitter.

Hubbard’s departure comes just months after he took over Twitter’s media team from Katie Stanton, who left the company in January together with a handful of other senior executives.

His role will now be filled by Ali Jafari, who has been leading the company’s Amplify video ad business. Jafari will still be in charge of Amplify, and also fill in for Messerschmidt. Twitter COO Adam Bain confirmed his new role with a tweet Thursday, saying that he was “fired up” for Jafari.

Bain also thanked Messerschmidt and Hubbard in a separate tweet. 

Twitter has been struggling to get back on a growth path in recent months, but investors have shown little patience with the company, sending with the stock now hovering sightly above  $14 after cratering at the end of April.

At its annual investor conference in San Francisco Wednesday, Twitter’s leadership nonetheless insisted that there is a path forward for the company as an independent entity. “This is a service that will endure decade after decade after decade,” CEO Jack Dorsey told investors.

Update: 1:33pm: This post was updated with comments from Twitter COO Adam Bain.