Twitter may be in big trouble when it comes to generating advertising revenue: GroupM, part of WPP, the world’s biggest ad company — and Twitter’s biggest spender — is reportedly telling its clients that buying ads on the platform is “high-risk,” according to Platformer and Digiday. That makes it the third advertising juggernaut telling massive corporations that they might want to take their money elsewhere, after IPG and Omnicom Media Group both recommended stopping advertisements on the platform.

GroupM works with companies like Google, L’Oréal, Bayer, Nestle, Unilever, Coke, and Mars. If you’ve ever seen that graphic about how a few brands make pretty much everything you buy at the grocery store, you’ll notice a lot of Venn diagrams overlap with GroupM’s list of clients.

GroupM is reportedly concerned about several specific things following Elon Musk’s takeover of Twitter; in a document, it cites the large numbers of Twitter executives leaving or being fired (especially those in charge of safety, security, and compliance), the wave of high-profile impersonations by “verified” users, and also raises concerns about Twitter’s abilities to follow the Federal Trade Commission’s orders. If Twitter wants to lose its high-risk label, there’s several things GroupM reportedly wants to see, according to a document viewed by Digiday and a Slack message from Twitter’s agency partnerships lead seen by Platformer. The list includes:

GroupM didn’t immediately respond to The Verges‘s request for comment. Twitter no longer has a communications department to reach out to such requests. The internal message seen by Platformer says that Twitter is “working through” GroupM’s requirements with leadership.

While Musk has said that he wants to wean Twitter off its reliance on advertising for revenue, he’s not there yet. For one, a lot of people can’t even buy the company’s premium Blue subscription service right now, because the company temporarily suspended that program. Musk has said that Twitter is burning through around $4 million a day, and he’s also saddled it with hefty interest payments on the debt he used to purchase it in the first place. Twitter needs money if it wants to keep going — but it seems that advertisers are increasingly hesitant to provide it.