KKR & Co. will buy Envision Healthcare Corp. for $46 a share after an almost yearlong sale process for the medical company, which staffs hospitals and runs surgery centers in the U.S.

The all-cash deal values Envision at $5.57 billion. Including debt, the acquisition is valued at $9.9 billion, the healthcare company said in a statement. Envision said the deal represents a 32 percent premium to its stock price in November, when it announced it was reviewing strategic alternatives.

Investors such as KKR and strategic buyers including health insurers have been snapping up healthcare assets in the U.S.

Last year, KKR finished raising money for a $1.45 billion healthcare fund dedicated to growth stage companies. Health insurance and services giant UnitedHealth Group Inc. has acquired a string of medical practices, and drugstore chain CVS Health Corp. is buying insurer Aetna Inc., with the goal of making CVS’s retail locations hubs for health services.

Envision’s strategic review started shortly after activist investor Starboard Value, run by Jeff Smith, revealed a stake in the company and said it would make an attractive takeover target. Corvex Management, another activist firm and shareholder, reduced most of its holdings in the first quarter.

In the months after the review started, Envision was said to draw interest from UnitedHealth and separate groups of private-equity firms interested in all or parts of the company. Those groups included a consortium comprised of Hellman & Friedman, Onex Corp. and Clayton Dubilier & Rice, as well as one led by Carlyle Group LP.