Kevin Mahaffey

Kevin Mahaffey said he was building software by age 8. Since then, the self-professed hacker has channeled his talent into starting the cybersecurity firm Lookout. He also serves as the chair of his wife’s startup, Stork Club, which partners with major insurance providers to help employees manage out-of-pocket costs for maternity and fertility care. As a successful angel investor, he also helps others build durable companies. Ten of the startups in his portfolio grew their private-market valuations to $1 billion or higher, including the workplace data-management startup People.ai, which hit its unicorn milestone in August. Trust is the key to his investing success, Mahaffey said. “Startups tend to be an emotional roller coaster, with things never as good or as bad as they seem,” he said. “The path can be lonely, and it’s always better knowing you have someone in your corner.”