While ChatGPT is still growing its user base, Sensor Tower says that growth is slowing down — ChatGPT increased its monthly active users by 168 percent in January, but only 78 percent in April. ChatGPT still has a “substantially larger user base” than its rivals, but its growth is also falling behind Claude’s. According to Sensor Tower, ChatGPT’s downloads were up 14 percent year over year over the past few months while Claude saw an 11x increase during the same period.

ChatGPT is experiencing this slowdown right as OpenAI is eyeing an IPO, although CFO Sarah Friar has reportedly expressed concerns about those plans. According to The Wall Street Journal, OpenAI recently missed its own internal targets for new users and revenue, sparking worries among Friar and other leaders at OpenAI that “the company might not be able to pay for future computing contracts if revenue doesn’t grow fast enough.”