The seemingly low-stakes world of text and email customer messaging revealed some big fortunes Wednesday, as marketing technology firm Klaviyo Inc. began trading in New York.

Andrew Bialecki founded the Boston-based company in 2012 and it grew rapidly, attracting investors including Summit Partners, Lone Pine Capital and Shopify. Klaviyo’s $30-a-share offering price valued it at more than $9 billion based on its fully diluted share count.

The stock rose 9.2% Wednesday to close at $32.76 in its trading debut.

That’s set to make Bialecki, 37, very rich. He still owns about one-third of Klaviyo, making him the company’s largest shareholder, a stake worth $3.2 billion, according to the Bloomberg Billionaires Index. Born into a family of small business owners, Bialecki calls himself a proponent of ownership and independence.

“My advice to founders: Raise as little as you need and prove some traction with customers,” Bialecki told Inspired Capital’s Alexa von Tobel in a 2022 podcast. “Once you do that, fundraising for the rest of your life gets a lot easier.”

After studying physics, astronomy, and astrophysics at Harvard University, Bialecki joined retail analytics firm Applied Predictive Technologies as an engineer. He later worked at marketing software companies Performable and Rocktech Digital before starting Klaviyo, which enables businesses to create targeted marketing campaigns, track customer behavior, and analyze their performance.

He was joined by Ed Hallen, an MIT graduate who also worked at Applied Predictive Technologies and is now the company’s chief product officer. Hallen, 41, owns a stake in Klaviyo worth $1.1 billion, according to the Bloomberg Billionaires Index.

Bialecki and Hallen have already begun cashing in on their company’s success. Bialecki sold almost $30 million of stock in a repurchase program in 2020, while Hallen sold shares worth $90 million between 2020 and 2021.

Klaviyo had net income of about $15 million on revenue of $321 million for the first six months of 2023, compared with a loss of $25 million on revenue of $208 million for the same period last year. Its initial public offering raised $576 million.

In its prospectus, Klaviyo says efficiency “is part of our DNA.” Of the $455 million in primary capital it had raised before the company’s IPO, the company says it spent only $15 million in the operation of its business.

Klaviyo joins a mini-wave of companies going public in September, including Instacart and Arm Holdings Plc, ending the longest lull in US listings since the financial crisis.

“We believe in aiming long-term, getting close to the customers and being a disciplined company,” Bialecki said in a Bloomberg Television interview Wednesday. “I am excited for public shareholders, and to have them.” 

This article was provided by Bloomberg News.