KnowBe4 sold a security product built around a former hacker's name. Its main course was Kevin Mitnick Security Awareness Training, named for the hacker turned security consultant. KnowBe4's idea was that attackers walked past firewalls by fooling people. So it sent workers fake phishing emails and taught the ones who clicked. By the time it went public in April 2021, its founder had spent more than two decades in the security business.

Fixing the Human Layer

Stu Sjouwerman had worked in cybersecurity for 15 years when he started KnowBe4 in Clearwater, Florida, in 2010. He saw companies spend billions on security products and still get breached through a single click. KnowBe4 sold training and simulated attacks by subscription. A company could send its own staff a fake phishing email, see who fell for it, and assign short lessons. KnowBe4 later added PhishER, a tool for sorting the suspicious emails employees reported.

Sixteen Dollars to Vista

KnowBe4 priced its IPO at $16 a share in April 2021 and listed on Nasdaq as KNBE. The company sold 9 million new shares, and early holders sold more alongside them. In October 2022 Vista Equity Partners agreed to buy the company. The deal closed on February 1, 2023, at $24.90 a share in cash, and KnowBe4 left Nasdaq less than two years after its debut.

Cover: Life-Size Black Bass, Winslow Homer. Art Institute of Chicago, public domain. Chosen for a bass striking a lure (phishing).