Bloomberg Billionaires Index

View profiles for each of the world’s 500 richest people, see the biggest movers, and compare fortunes or track returns.

# 145 Jan Koum $12.9B

Random fact: Co-founded WhatsApp with former Yahoo colleague Brian Acton.


Koum is a co-founder and former chief executive of WhatsApp, a messaging app that has been downloaded onto more than six billion devices. The app was launched in 2009 and sold to Facebook, the world's largest social-networking company, for $22 billion in 2014. Koum was a Facebook director for 3.5 years before leaving in 2018.

As of :
Last change +$50.0M ( +0.4%)
YTD change +$475M ( +3.8%)
Biggest asset Cash
Country / Region United States
Age 46
Industry Technology
View net worth over:   Max 1 year 1 quarter 1 month 1 week

Relative Value

Jan Koum's net worth of $12.9B can buy ...

troy ounces of gold
barrels of crude oil

... and is equivalent to ...

of the GDP of the United States
of the total wealth of the 500 richest people in the world
of the top 100 U.S. college endowments
of the top 200 U.S. executives’ total awarded compensation
of U.S. existing home sales
times the median U.S. household income

Latest News

Net Worth Summary

Private asset
Public asset
Misc. liabilities
Confidence rating:

The majority of Koum's fortune is derived from the proceeds he received after selling WhatsApp to the world's largest social-networking company for $22 billion in cash and stock in February 2014. He owned about 43% of the company at the time of the sale, according to a Bloomberg analysis of October 2014 SEC filings. The billionaire received more than 76 million shares of Facebook and almost $2 billion in cash in the transaction, according to an October 2014 filing with the US Securities and Exchange Commission.

WhatsApp has been downloaded onto more than six billion devices as of September 2021, according to data from app intelligence firm Sensor Tower cited in a Bloomberg article. Koum sold $8 billion worth of shares between 2015 and when he left the firm in 2018, according to a Bloomberg analysis of stock exchange filings. His remaining holding of about $2 billion in Facebook shares wasn't disclosed in subsequent filings and was assumed to have been sold in a May 31, 2019 update to this analysis.

Koum has spent more than $300 million on three residential properties near Los Angeles, California since 2019, according to February 2021 news reports. These are included here at cost prices.

The value of his cash investments is based on an analysis of share sales, dividends, market performance, taxes and charitable contributions.


Family: Married, No children

Koum was born and raised in a village outside of Kiev, Ukraine, the only child of a housewife and a construction manager. He immigrated to California with his mother at age 16, enrolling at San Jose State University and working at Ernst & Young as a security tester. He got a job as an infrastructure engineer at Yahoo in 1997, where he met his future business partner Brian Acton. Koum's father died the same year; his mother died three years later.

Koum left Yahoo in October 2007. He started mobile-messaging service WhatsApp on Feb. 24, 2009, his birthday. Six months later, Acton persuaded five former Yahoo colleagues to invest $250,000 in seed funding, and was granted co-founder status and a stake in the company. Sequoia Capital invested about $58 million in the startup in multiple stages.

Facebook, the world’s largest social network, agreed to purchase WhatsApp in February 2014 for $22 billion in cash and stock, the biggest Internet acquisition in more than a decade. He announced he was leaving WhatsApp in an April 30, 2018 Facebook post.

  • 1976 Jan Koum is born near Kiev, Ukraine.
  • 1992 Immigrates to Mountain View, California, with his mother.
  • 1997 Starts working as infrastructure engineer at Yahoo. Father dies in Ukraine.
  • 2007 Leaves Yahoo. Spends year traveling South America and playing frisbee.
  • 2009 Starts mobile-messaging service WhatsApp on his birthday.
  • 2011 Venture capital firm Sequoia Capital invests in WhatsApp.
  • 2014 Facebook buys WhatsApp for $22 billion in cash and stock.
  • 2018 Announces his departure from WhatsApp.