Jan Borysovych Koum is a Ukrainian-American businessman, the self-made billionaire co-founder and former CEO of WhatsApp, the world's largest mobile messaging service. Born in Kyiv, Ukrainian SSR, in 1976 into a Jewish family, his early life was marked by poverty and hardship: he immigrated to Mountain View, California, at age 16 with his mother and grandmother, living on social support.

Koum worked as a cleaner at a grocery store and dropped out of San Jose State University to work as an infrastructure engineer at Yahoo!. His pivotal career moment came in 2009 after buying an iPhone: he recognized the potential of the App Store to create a whole new industry, leading him to found WhatsApp (named because it sounded like what's up).

• WhatsApp (Co-founder & Former CEO): The core wealth generator, the world's largest mobile messaging service. Acquired by Facebook for $19.3 billion in 2014.
• Early Struggles: He immigrated with his mother at age 16, relying on social support and working as a cleaner to make ends meet.
• Anti-Ad Stance: His founding philosophy centered on privacy and a strict no-ads policy.
• Final Exit: He resigned from WhatsApp and Facebook's board in 2018 due to disputes with Facebook over the company's commitment to user data and the ad-free model.

Jan Koum co-founded WhatsApp in 2009 with Brian Acton (who invested the $250,000 seed funding). The early versions were unpopular, but the launch of Apple's push notification ability in June 2009 turned the product into a full-fledged messaging service, quickly gaining a massive user base. The decisive financial event was the $19.3 billion sale of WhatsApp to Facebook in 2014 (one of the largest tech acquisitions in history).

Koum signed the deal in the abandoned building where he once collected food stamps as a teenager—a powerful symbol of his journey from poverty to wealth. He sold over $2.4 billion worth of Facebook stock before his contentious resignation in 2018. He now invests through his firm Newlands, building a portfolio of startups. His immense wealth is secured by the successful monetization of his social media platform.

Jan Koum's social impact is massive and structural, tied to WhatsApp's role in transforming global communication and providing low-cost/free messaging to billions of users worldwide. The company's technology is foundational to global digital connectivity.

His personal philanthropy supports various educational and community initiatives. His career is a testament to the profitability of disciplined software engineering and unwavering commitment to a product vision (simplicity, no ads), leading to one of the largest tech exits in history.

Jan Koum maintains the casual, functional style of a technology founder. His attire is consistently simple and unostentatious. His aesthetic reflects his commitment to privacy and simplicity (the guiding principles of his app).

Residing in Atherton, California, his luxury is the immense security and financial reward derived from his multi-billion dollar fortune. His life is dedicated to technology investment, philanthropy, and his personal pursuit of simplicity and anti-commercialization in the digital realm.