Slim's fortune has swelled to an estimated $53.5 billion, up $18.5 billion in 12 months. Shares of America Movil, of which Slim owns a $23 billion stake, were up 35% in a year.
That massive hoard of scratch puts him ahead of Microsoft cofounder Bill Gates, who had held the title of world's richest 14 of the past 15 years.
Gates, now worth $53 billion, is ranked second in the world. He is up $13 billion from a year ago as shares of Microsoft rose 50% in 12 months. Gates' holdings in his personal investment vehicle Cascade also soared with the rest of the markets.
Buffett's fortune jumped $10 billion to $47 billion on rising shares of Berkshire Hathaway. He ranks third.
The Oracle of Omaha shrewdly invested $5 billion in Goldman Sachs and $3 billion in General Electric amid the 2008 market collapse. He also recently acquired railroad giant Burlington Northern Santa Fe for $26 billion.
In his annual shareholder letter Buffett wrote, "We've put a lot of money to work during the chaos of the last two years. When it's raining gold, reach for a bucket, not a thimble."
Many plutocrats did just that. Indeed, last year's wealth wasteland has become a billionaire bonanza. Most of the richest people on the planet have seen their fortunes soar in the past year.