(Undated) -- Bill Gates is again the richest man in the world. The Microsoft founder tops the latest Bloomberg Billionaires Index, released today.

Gates' fortune grew by $15.8 billion dollars in 2013, more than anyone else on the list. That pushes his wealth to $78.5 billion dollars Gates reclaimed the "world's richest" title from Mexican investor Carlos Slim in May.

A 40-percent rise on Microsoft stock fueled the growth in Gates' net worth. The Bloomberg Index reports the total net worth of the 300 wealthiest people on Earth stood at $3.7 trillion dollars when trading on the world's stock markets closed on December 31st.