Western Digital has today agreed to purchase flash storage company SanDisk in a deal worth around $19 billion, paving the way for the hard drive manufacturer to expand into the growing NAND market.

The deal will see Western Digital pay $86.50 per share for SanDisk, which includes $85.10 per share in cash, and "0.0176 of a Western Digital common share", according to a statement released to Bloomberg. Following the news, SanDisk shares rose 6.2% to $79.84 in pre-market trading, while trading of Western Digital shares was halted.

The buyout of SanDisk gives Western Digital a strong foothold in the growing NAND storage market, allowing the company to produce everything from solid state drives to memory cards. SanDisk is currently the third-largest producer of NAND flash in the world, behind Toshiba and industry leader Samsung.

Purchasing SanDisk makes perfect sense for Western Digital. While the company is one of the largest hard drive manufacturers, along with Seagate, the industry is slowly moving away from hard disk storage in favor of faster, smaller solid state drives. In their recent financial year, Western Digital saw sales decline by four percent as a sign of things to come.

Of course a deal of this magnitude isn't going to be completed immediately. Western Digital expects their $19 billion purchase of SanDisk to close in the third quarter of 2016, providing it gets the necessary approvals from regulatory bodies.