Corning Inc.'s core sales and earnings per share increased in the second quarter, with a pre-market stock price drop of over 15%

Corning Inc.'s core sales for the second quarter were $4.74 billion, a year-on-year increase of 17%; The core earnings per share were $0.78, a year-on-year increase of 30%; Corning Inc.'s pre-market stock price in the US fell more than 15%.