• Salesforce is losing a number of key execs in the wake of Bret Taylor's departure.

• Slack CEO Stewart Butterfield is also departing, along with some other product-focused execs.

• The departures come as Salesforce's growth has slowed and it's facing tough questions.

Salesforce is in the midst of a serious brain drain at the highest levels. Last week, co-CEO Bret Taylor made the surprise announcement that he'd be departing the company.

Shortly afterwards came the news that Mark Nelson, the CEO of Salesforce subsidiary Tableau, and Steven Tamm, a CTO at the cloud tech giant, are also departing. In November, the company also said Gavin Patterson, the company's chief strategy officer who had previously been its chief revenue officer will depart at the end of January.

Then, earlier this week, Insider reported that Stewart Butterfield, CEO of Slack — the workplace chat app that Salesforce acquired in 2021 for $27.7 billion —will be leaving the company in the new year. Tamar Yehoshua, Slack's chief product officer, is also resigning, as is Slack senior VP of communications Jonathan Prince.

It's not clear if the timing of all these departures is anything more than coincidence: In a memo to employees, Butterfield wrote that his plans to depart have nothing to do with Taylor's, as Insider earlier reported.

Still, it comes at a critical moment for Salesforce and its now-sole CEO Marc Benioff. The company's stock is down some 48% from the beginning of the year, as the larger tech downturn takes its toll on the markets. Salesforce has warned investors that a slowing economy is making it more difficult to close deals as IT spending stalls out, even as investors push Benioff to demonstrate a commitment to improving its profit margins.

And the specific executives who are hitting the exits represent some of Salesforce's biggest bets on the future. Taylor himself was seen as a product visionary who would help Salesforce break into new markets, as seen when he masterminded the Slack acquisition. Indeed, Slack and Tableau represented Salesforce's two largest acquisitions in its history, as it invested in new lines of business.