Twitter is seeing some big changes: The departure of four executives is confirmed, following reports from earlier today.

In a tweet, CEO Jack Dorsey announced that senior vice president of engineering, Alex Roetter; senior vice president of product, Kevin Weil; global media head, Katie Stanton; and vice president of human resources, Brian “Skip” Schipper have resigned.

Dorsey sought to emphasize in his tweet that every one of the executives left the company voluntarily. The news, which was first revealed by Re/code, is echoed by the departure of others, including Jason Toff, who headed the six-second video platform Vine — he’s rejoining Google to work on virtual reality.

The company has enacted a temporary transition plan in which chief operating officer Adam Bain will oversee not only the revenue-related product teams, but also the media and human resource departments. Chief technology officer Adam Messinger has been tasked with combining the engineering, consumer product, design and research, user services, and fabric teams into one group. Dorsey said that he’ll be working with Messinger to facilitate this transition.

All of this comes amid rumors that Twitter will soon be hiring a chief marketing officer to manage an area that is currently overseen by the company’s chief financial officer, Anthony Noto, and will also be hiring a new public relations chief, to handle a department currently under the guidance of general counsel Vijaya Gadde.

In an interview with AdAge in August, Noto talked about his time as the interim marketing chief. When asked about the hiring of a CMO, he said that Twitter was talking to “a wide spectrum of people” and that the role would be a “marketer’s dream”:

The delightful thing that I have found is that many of the people we’re talking to really think of the opportunity at Twitter as a once-in-a-lifetime opportunity. I think of it as a marketer’s dream. We have this incredibly impactful brand, but a significant amount of the world still doesn’t use our product. Seventy percent of the people still do not use Twitter. It’s an opportunity to take that great brand with all of that awareness and making it relevant and useful for everyone.

Maybe the CMO can work on addressing the ad campaign that Twitter launched ahead of the baseball World Series — commercials that were panned by users of the service.

How investors in the public company are reacting to the news isn’t clear quite yet, as the stock market won’t open for a few more hours. However, the departures of more executives may cause concern about the state of Twitter. The company’s stock has dropped considerably from a high of $69 in January 2014  to close at $17.84 on Friday. Twitter started off as a publicly traded company at $45.10, after being priced at $26, but with investors worried about the sluggish growth in user numbers, the price has just gone down.