Two years ago, Ben Chestnut found a crumpled piece of paper in the trunk of his Mercedes GL63 SUV, alongside the muddy shoes and helmets he uses while mountain biking in the hills of northern Georgia. Forgotten there for a year, the paper assessed how much a top private equity firm in New York thought his company was worth: $2 billion. The CEO of Mailchimp stashed it in his personal safe along with the business cards of some America’s deepest-pocketed financiers—for his wife to shop a sale in the event of his death, but not a minute before. “That’s my retirement plan,” Chest nut quips.
The Forbes 400 newcomer has good reason not to rest. Chestnut and his cofounder, Dan Kurzius, have both profited richly from their patience. With $600 million in revenue, Mailchimp is in the black and has more than doubled its estimated valuation to $4.2 billion in the last two years, giving Chestnut, 44, and Kurzius, 46, its sole owners, stakes worth $2.1 billion each.
Mailchimp’s success is built on the backs of America’s small business owners. Its most popular service—email marketing—might seem a low-tech, unsexy medium in 2018. But small business owners usually can’t afford marketing teams or social media pros. To the 20 million people on Mailchimp today, the ability to send a sleek, on brand email with just a few clicks can mean the difference between bankruptcy and success.
Chestnut and Kurzius have worked to keep t