Billionaires Richer than Ever

Forbes' latest annual ranking of the nation’s billionaires found the top 400 wealthiest Americans are worth a combined total of $2.29 trillion, the wealthiest group since the magazine began keeping track 33 years ago. The magazine attributes the increase in part to recent record highs in the U.S. stock market.

Bill Gates and Warren Buffet top the list this year, while Charles Koch and former mayor Michael Bloomberg are the wealthiest New Yorkers.

Forbes added 27 newcomers to the list, among them, hedge-fund titans and technology entrepreneurs.

Real Estate developer David Walentas, who made his fortune redeveloping Brooklyn’s Dumbo neighborhood, saw his net worth increase to $1.7 billion, putting him on the list for the first time at number 368. Walentas was an early investor in Brooklyn’s turnaround, buying two million square feet of industrial space for $12 million in the 1970s.

Also new to this year's list, Elizabeth Holmes, a 32-year old college dropout. She used the money she saved for school to found Theranos, a blood-testing company that promises faster results at better prices than those at commercial labs. Theranos was recently valued at $9 billion.

Holmes is the youngest woman on the list, but not the youngest person. That honor goes to early Facebook employee, Dustin Moskovitz, who is just a few days younger than Facebook founder, Mark Zuckerberg.

Zuckerberg just missed the top ten cut off, coming in at number 11. Forbes calculates he has a net worth of $34 billion. He saw his wealth increase more than any other member on the list.

With a minimum net worth of $1.55 billion needed to qualify for the list, 113 billionaires didn’t make the cut this year for the top 400 list.