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Jan Koum immigrated to the United States from Ukraine with little money, learned computer networking, worked at Yahoo and then cofounded WhatsApp, whose sale to Facebook created his fortune. [1][2][3]
Immigration, Yahoo and WhatsApp
Koum grew up near Kyiv and moved to California with his mother as a teenager. His family relied on public assistance while he taught himself computer networking and later studied at San Jose State University before leaving school for technology work. [2]
He joined Yahoo in the late 1990s and spent nearly nine years there before leaving. In 2009 he cofounded WhatsApp with former Yahoo colleague Brian Acton, building a simple mobile messaging service around phone numbers rather than advertising-heavy social profiles. [1][2]
Facebook agreed to acquire WhatsApp in 2014 in a cash-and-stock transaction that ultimately valued the company at roughly $22 billion. Koum's founder stake in WhatsApp created his billionaire wealth, making the path one of company creation after a materially disadvantaged immigrant start rather than inherited capital. [3][1][2]
Sources for background
Sources reviewed Sep 14, 2026.
- Jan Koum · Forbes · Jul 15, 2026
- Exclusive: The Rags-To-Riches Tale Of How Jan Koum Built WhatsApp Into Facebook's New $19 Billion Baby · Forbes · Feb 19, 2014
- Facebook to Acquire WhatsApp · Meta · Feb 19, 2014
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