Corning Stock Has Lost Half Its Value Since June. Is It a Buy Before Its Next Report?

Shares of glass and fiber-optics maker Corning (NYSE:GLW) have had a wild 2026. The stock almost tripled between January and late June, closing at a record $255.69 on June 29. At roughly $125 as I write, shares are now down about 51% from that peak -- including an 8% fall on Oct. 22 alone.

But the company is growing fast. Corning's second-quarter core earnings per share, its non-GAAP (adjusted) measure, climbed 30% year over year. Management also forecast around 28% growth in the third quarter.

Corning posts those third-quarter results on Tuesday, Oct. 27. And despite its recent losses, the stock's still up over 40% for 2026.

Image source: The Motley Fool.

What caused the drop?

I'd say much of the decline reflects a stock giving back a rally that got ahead of the business.

In May, Corning announced a long-term partnership with Nvidia under which it plans to grow its U.S. optical connectivity manufacturing capacity tenfold. Amazon then signed a multiyear, multibillion-dollar deal for Corning to supply optical fiber, cable, and connectivity products for its U.S. data centers.

Investors poured in. At its June peak, the stock was valued at around 95 times Corning's adjusted earnings in the prior four quarters.

Shares then sank about 46% in July, including a 12% drop on July 28 -- when Corning released second-quarter results with core earnings per share up 30%. Management's third-quarter forecast put core sales growth at around 16%, a bit under the second quarter's 17% rate.

On Sept. 11, Corning signed an agreement letting it issue up to $2 billion in new shares from time to time. Shares sank around 14% the next trading day. But at today's price, $2 billion is under 2% of what the whole company is worth (about $108 billion).

October has been tough, too. Shares are down around 19% so far this month, and the Oct. 22 drop was on a day the Nasdaq Composite slid over 2%.

Optical's boom

Meanwhile, the business keeps improving. And one segment explains most of it.

Showing how central data centers have become to Corning, optical communications sales climbed 32% year over year to $2.07 billion in Q2. That followed growth of 24% in Q4 2025 and 36% in Q1 2026. In the segment, enterprise network sales (which include fiber products for hyperscale data centers) jumped 65%. And the segment's net income soared 77%.

Not only did optical communications make up around 44% of Corning's Q2 sales, compared with 39% a year before, but it also provided about $506 million of the $693 million year-over-year rise in core sales. In other words, about three-quarters of Corning's growth came from this one segment.

The shift is showing up in profits. Core earnings-per-share growth has accelerated, from 24% in Q3 2025 to 26% in Q4 and 30% in both Q1 and Q2 of 2026. Core sales growth, meanwhile, has stayed in the mid-to-high teens, so profits are rising almost twice as fast as sales. Core operating margin widened 1.9 percentage points to 20.9% in Q2.

Management's internal plan targets an annualized sales run rate of $40 billion by the end of 2030, over double the second quarter's pace of around $19 billion.

The stock finally looks reasonably priced

The sell-off has also cut the stock's valuation sharply. Shares now sell at around 44 times adjusted earnings for the past four quarters, under half the price-to-earnings ratio at the June peak. Plus, they cost about 29 times analysts' consensus 2027 earnings estimate.

For a company growing core earnings per share around 30%, I think this forward price-to-earnings ratio looks reasonable.

Of course, the risks haven't gone away. Much of Corning's growth relies on a few tech giants continuing to spend heavily on AI data centers, and any cutback there could hit the optical business hard. The stock has also shown it can drop 8% or more in one day. And if Corning uses its share-issuance agreement, current holders could have their stakes diluted.

So, is Corning a buy ahead of Tuesday's report?

I think the sell-off has made it worth a look. Given how much the stock can swing after a report, though, I'd be comfortable taking a position here and building it over time.

Daniel Sparks and his clients do not have positions in any of the stocks mentioned. The Motley Fool has positions in and recommends Amazon, Corning, and Nvidia. The Motley Fool has a disclosure policy.