William Blair initiated coverage of Aaon with an Outperform rating. The analyst says Aaon is a “best-in-class” commercial heating, ventilation and air conditioning systems company that is gaining share “from the big dogs.” The company’s core packaged commercial rooftop systems segment is quickly growing share beyond its current 11%, the analyst tells investors in a research note. The firm believes Aaon has scope over the longer-term to increase sales in the low to mid-teens, above market levels, leading to 15%-plus EBITDA growth.