From Apple’s press release:

Apple today announced Corning Incorporated will receive $200 million from Apple’s new Advanced Manufacturing Fund as part of the company’s commitment to foster innovation among American manufacturers. The investment will support Corning’s R&D, capital equipment needs and state-of-the-art glass processing. Corning’s 65-year-old Harrodsburg facility has been integral to the 10-year collaboration between these two innovative companies and will be the focus of Apple’s investment.

And:

Apple has committed to investing at least $1 billion with US-based companies as part of the fund, which is designed to foster innovative production and highly skilled jobs that will help lay the foundation for a new era of technology-driven manufacturing in the US.

Logical investment in a company whose fortunes are tightly bound with yours.