According to Forbes, 38-year-old Jan Koum, who ranks 202 in the list, is now worth $6.8 billion and 42-year-old Brian Acton (rank 551) is worth $3 billion.
(Also see: Facebook to buy WhatsApp in a $19 billion deal)
Run by just 55 employees, WhatsApp has over 450 million active users.
Koum and Acton are among 26 newcomers who made it fresh to the annual list, alongside Twitter's Evan Williams, who has a fortune of $3 billion.
Microsoft founder Bill Gates topped the list with his $76 billion fortune. Gates has topped the list in 15 of the last 20 years.
The Microsoft Corp co-founder reclaimed the top spot after a four-year hiatus, toppling Mexico's telecommunications mogul Carlos Slim Helu. Slim came in second with his fortune of $72 billion.
A record 1,645 billionaires with a total net worth of $6.4 trillion made Forbes' list, up from 1,426 last year. Just over 10 percent were female, with 172 women compared with 138 a year earlier. This year's annual rich list has the largest number of female billionaires ever, said Forbes.
Wal-Mart Stores Inc heiress Christy Walton was the highest-ranking woman, in ninth place, at $36.7 billion. France's Liliane Bettencourt, who got much of her wealth from cosmetics company L'Oreal SA, was next among women at $34.5 billion, and ranked 11th overall.
The Internet was well-represented. Google Inc founders Larry Page and Sergey Brin ranked 17th and 19th, worth a respective $32.3 billion and $31.8 billion, while Amazon Inc's Jeff Bezos was between them at $32 billion.
However, according to the Forbes report, it was Facebook founder Mark Zuckerberg who made the most money in the world over the past year.
From 2013's estimate of $15.2 billion to $28.5 billion this year, Zuckerberg's net worth nearly doubled within one year.
Written with agency inputs
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