The PE firm making billions off the Klaviyo IPO only 4 years after investing

man in sweatshirt stares at the camera (Credit: Barry Chin—The Boston Globe/Getty Images)

Of all the winners and losers from last week's spate of IPOs, one private equity firm, Summit Partners, stands to reap particularly sweet gains. 

Klaviyo, a marketing and automation company, is one of three IPOs, including Arm Holdings and Instacart, that were expected to jumpstart the IPO market this past month.