Insulet (PODD) shares suffered the biggest losses of any S&P 500 stock on Friday, falling 8.8% after the insulin treatment device maker suggested that new user growth in the second half of 2024 may be lower than previously expected, despite beating second-quarter revenue estimates.

Insulet reported diluted earnings of $2.59 per share on revenue of $488.5 million, up from the year-ago period and beating analyst estimates compiled by Visible Alpha. The revenue gains were boosted by a 26.3% year-over-year jump in sales of the company’s Omnipod device.

However, adjusted earnings per share of 55 cents fell slightly short of expectations as the company included the impact of a $13.5 million charge in the quarter related to inventory that it expects will continue to be underutilized.

User growth may be lower than expected

The company still expects user numbers to increase in the second half of the year, but indicated that the pace of growth may be slower than initially expected due to a lower number of patients switching from competing devices to its products.

In a note following the earnings release, Baird analysts said they had heard concerns from investors about user growth, particularly in the U.S., but said Insulet could potentially see further quarter-over-quarter improvements in global new patient numbers this year.

Baird maintained an outperform rating and $238 price target on Insulet shares, highlighting the company’s increasing margin strength and potential for global revenue growth.

The company increased its forecast for full-year sales growth from 14 to 18 percent to 16 to 19 percent.

With Thursday’s losses, Insulet shares have fallen about 16 percent since the beginning of the year.