Corning issued lighter-than-expected third-quarter sales guidance, overshadowing a better-than-expected second quarter that was driven by artificial-intelligence demand.

Corning expects core sales for the current quarter to grow by about 16%, to between $4.9 billion and $5 billion. Analysts expected $5 billion for the quarter.

Core earnings per share, an adjusted figure, is expected to grow by 28% to a range of 85 cents to 89 cents a share. Analysts expect 85 cents a share.

Shares fell 17% in premarket trading to $119.54 on Tuesday.

Corning has been betting that the massive infrastructure demands of AI will drive its next wave of growth, relying on its specialized optical fiber to link hyperscale data centers. The shift away from stagnant telecom-carrier spending toward enterprise hyperscalers has won over Wall Street, and Corning's stock has more than doubled over the past 52 weeks as of Monday's close.

The specialty glass, ceramics, and optical fiber posted net income of $559 million, or 64 cents a share, compared with $469 million, or 54 cents a share, in the same quarter a year earlier.

Core earnings per share, which strips out exceptional items and one-off costs, came to 78 cents a share. According to FactSet, analysts were expecting 76 cents a share.

Sales rose 17% to $4.74 billion, topping analyst forecasts that pegged revenue at $4.63 billion.

The company's optical-communications business grew sales by 32% to $2.07 billion, including a 65% increase in enterprise networks, where its generative-AI product sales grew significantly faster, it said.

Corning's solar segment swung to a loss of $7 million, from a profit of $2 million a year earlier, despite sales rising 90% after completion of an extended maintenance shutdown and equipment upgrade at its solar-wafer facility.

Management expects profitability to improve in the third quarter, the company said.