Your boss’s mood and behavior can affect how everyone else around them performs at work. But the happier your boss is, the happier their employees are—and that tends to have a positive impact on both the company’s bottom line, and its market performance.

That’s the conclusion from Arthur C. Brooks, a Harvard professor who teaches courses on leadership and happiness at both the Harvard Kennedy School and Harvard Business School. Speaking recently at Harvard Business School’s Klarman Hall for an episode of the HBR IdeaCast, Brooks said “happier employees are more profitable, more productive employees. That’s just the way it is. If you can have a happier workforce, you’re going to have a better company. And the results are going to be there.”

Brooks, a bestselling author whose recent book Build the Life You Want was co-written with Oprah Winfrey, said leaders who know how to prioritize their happiness will learn it “really, really is a good investment.”

The business case for happiness at work

Research from Irrational Capital, a Wall Street investment firm Brooks has advised, shows a clear financial correlation between employee happiness and company performance. The firm analyzed data from 7,500 publicly traded companies, including the entire S&P 500 and Russell 1000.​