Private equity firm American Securities has grounded KKR.

The firm announced Tuesday morning it had reached a $2.5 billion merger agreement to pay $43 a share for Air Methods, an emergency medical helicopter operator.

KKR was expected to win the auction after final bids were taken in the last few days, a source close to the process said.

Henry Kravis’ firm in 2015 bought Air Medical Group Holdings, a rival emergency-rescue firm, and was expected to combine the businesses.

Goldman Sachs and Centerview Partners advised the sell-side. In years past, when the leading investment banks sold a company in an auction involving private equity firms, and the auction was close the largest private equity firm would often end up winning. That is because a firm like KKR is a better source for future business.

However, the playing field is more level now.

American Securities in early 2015 closed on a $5 billion buyout fund, saying it targeted companies with between $50 million and $200 million in Ebitda. Air Methods annual adjusted Ebitda is about $300 million.

Air Methods says it is the largest domestic air medical transport provider in the $5 billion air medical market, serving 48 states with over 300 bases of operations. It also owns Specialty Care, a provider of outsourced operating room services including minimally invasive surgical support.

The Englewood. Colo.-based business also maintains a leading position in the complementary air tourism business.