The nation's largest helicopter air ambulance provider, Air Methods, has agreed to be acquired by affiliates of investment firm American Securities Corporation for $2.5 billion in cash plus net debt, the company announced yesterday.

The purchase price is the equivalent of $43 per share, a 20.4 percent premium to the traded share price of $35.70 on Jan. 31, 2017. Air Methods had been under pressure from some shareholders to take measures to increase the value of its stock, including exploring the possible sale of the company. The deal is expected to close by the end of the second calendar quarter of 2017.

“American Securities offers us a great opportunity to continue to invest and pursue long-term growth with greater operational flexibility, and we look forward to working with such a sophisticated private equity investor," said Air Methods CEO Aaron Todd.

Air Methods has seen its revenues increase in recent years, but earnings have remained relatively flat. In addition to air ambulances, Air Methods also operates two heli-tourism companies and the United Rotorcraft completion and modification business.