Shares of Corning ( GLW ), a beneficiary of the artificial intelligence (AI ) boom, tumbled Tuesday after the specialty glass maker’s second-quarter results and current-quarter guidance missed analysts’ expectations.

The company’s shares soared earlier this month after it lifted its second-quarter adjusted earnings guidance on AI fueling demand for its optical products. But on Tuesday, its shares plunged 8.5% as of 12:30 p.m. ET on GAAP Q2 results that missed estimates and a disappointing third-quarter outlook.

Corning said that it expects core sales to grow to about $3.7 billion in the third quarter, with core earnings per share (EPS ) in the range of $0.50 to $0.54. Analysts polled by Visible Alpha had been expecting $3.75 billion and $0.55, respectively.

Q2 GAAP Results Also Miss; Adjusted Figures Better

For the second quarter, Corning reported EPS of $0.12 on revenue of $3.25 billion, while analysts were looking for $0.33 and $3.36 billion, respectively.

However, Corning’s adjusted Q2 figures were stronger. It posted core EPS of $0.47, topping its own raised guidance, on $3.6 billion in core sales, which matched its revised expectations. The core EPS figure matched Visible Alpha estimates and core sales narrowly beat them.

Chief Executive Officer (CEO ) Wendell Weeks said the results were “driven primarily by the strong adoption of our new optical connectivity products for generative AI.”

Despite their slump Tuesday, Corning shares have gained 28% year-to-date.