Voce Capital's Dan Plants

Air Methods (AIRM) on Tuesday agreed to be acquired by buyout shop American Securities in a $2.5 billion deal that was struck as the emergency medical helicopter company's board faced an imminent director-election proxy fight launched by an activist hedge fund manager who had been publicly pushing for a sale since 2015.

American Securities agreed to acquire Air Methods shares for $43 a share in cash, representing a 20.4% premium to the company's stock price on Jan. 31, before press speculation around a deal emerged. The $2.5 billion enterprise value of the deal includes debt.

And the deal comes in the aftermath of a one-and-half year public activist campaign waged by activist Voce Capital Capital Management's Dan Plants. In September 2015 Plants reported a 4.9% stake and launched a campaign urging the Englewood, Colo.-based company to hire a financial adviser and explore a sale or privatization of the business.

In November of that year, Air Methods reported that it was working with Goldman Sachs and Bank of America to assess options for shareholders. However, by February the company said it had completed its review and determined that staying independent was in the best interest of shareholders.

As the review was proceeding, last year, Air Methods avoided a proxy contest launched by Voce by agreeing to expand its board to 12 members and adding one dissident director candidate sought by Plants. Also, in what in retrospect was a crucial victory for Plants, Air Methods also amended its bylaws as part of its deal with Plants to require all board members be elected annually, rather than in staggered terms.

A declassified board set the stage for a resurgent Plants in 2017. Likely discouraged by the company's failure to sell itself, Plants launched another director-election contest, this time seeking to elect four dissident directors to the company's board. The contest had been scheduled for an annual meeting set for May 17.

Nevertheless, at this stage, it is unclear whether Plants is satisfied with the deal price since the company has been a position in Voce's portfolio since 2011 and he has not been required to disclose share purchase prices. Plants declined to comment. It's possible, though unlikely that Plants could agitate to block the deal if he believed Air Methods could find a buyer willing to pay more.

Over the past couple years, Plants had backed his campaign by arguing that Air Methods "had serious operational issues," which included his assertion that the company did a poor job integrating a company it recently acquired. He also complained that it had over-tenured board members that are too cozy with management. Governance experts typically start to raise red flags when directors have been on boards for more than ten years. According to relationship mapping service BoardEx, a unit of TheStreet, independent directors Ralph Bernstein, 60, and Morad Tahbaz, 62, have each been on the Air Methods board for over 23 years.

And American Securities isn't the first private equity firm to buy into the sector. In 2015 Kohlberg Kravis Roberts & Co. LP (KKR) acquired Air Medical Group Holdings LLC, Air Methods' closest rival with 231 base locations in 34 states, from Bain Capital LLC and Brockway Moran & Partners Inc. for about $2 billion.

Air Methods currently transports about 100,000 patients annually via a fleet of more than 400 aircraft. 

* David Marcus contributed to this report