The tech company’s shares were down more than 2% to $9.73 in early trading on Monday after its chief strategy officer Imran Khan announced plans to leave his position. In a Securities and Exchange Commission (SEC) filing, Snap said that Khan will remain with Snap during a transitional period. He told CNBC in an emailed statement that “the time is now” to leave Snap. He called it a “difficult decision” and said that Snap will be guided by “a stellar leadership team.”

Khan joined Snap in 2015 from his role as an investment banker at Credit Suisse. He’s widely viewed as a critical player in Snap’s operation.

However, Snap has been working through some troubled times of late, including concerns over the design of its popular Snapchat app. Shareholders are also concerned about the company’s advertising efforts and whether it’ll be able to generate a profit at some point—something that has proven elusive so far.

Losing Khan, the company’s chief strategy officer, has apparently concerned shareholders. In a statement to CNBC, Snap chief executive Evan Spiegel thanked Khan for his time with the company and wished him good luck in the future.

Snap did not immediately respond to a Fortune request for comment on Khan’s departure.