Mark Zuckerberg added almost $3 billion a month to his net worth this summer

Key Points
  • Facebook had the best three-month rally among the five most valuable tech firms.
  • The rise added about $8 billion to Mark Zuckerberg's fortune, putting him right behind Warren Buffett on the billionaires list.
  • He also traveled across the country and welcomed a new baby.
Priscilla Chan and Mark Zuckerberg
Adam Berry | Getty Images

The stock market was kind to Mark Zuckerberg this summer.

So was life in general.

Facebook shares jumped 14 percent in the past three months, as of Thursday's close, the best performance among the five most valuable U.S. technology companies. Apple and Microsoft each rose about 7 percent, While Amazon and Alphabet dropped.

As Labor Day weekend arrives and the kids return to school, Zuckerberg finds himself the world's fifth-richest person, just behind Warren Buffett and ahead of Carlos Slim. Facebook's summertime rally added over $8 billion to the founder's fortune, which now sits at $71.7 billion, according to the Forbes billionaires list.

At 33, Zuckerberg is 54 years younger than Buffett, who amassed his fortune through many decades of value-based investing. Zuckerberg earned his wealth by creating an online business that's grown rapidly around the globe and now has 2 billion users.

The Harvard University dropout started the vacation season by returning to his alma mater to deliver the commencement address at graduation and collect an honorary degree.

In his speech (reprinted here in full), Zuckerberg urged graduates to help build a world where everyone has a sense of purpose. He also added his name to the list of tech executives calling for a universal basic income.

Zuckerberg's charitable organization — the Chan-Zuckerberg Initiative — has grown thanks to his regular stock sales. The entity, which he started with his wife, Priscilla Chan, has close to 200 employees, including a group of scientists hoping to identify every human cell.

As if that's not enough, Zuckerberg and Chan welcomed their second daughter last month. The birth of baby August prompted Zuckerberg to plan a two-month leave from his job, the first month right away with the second in December. Facebook allows for four months of maternity or paternity leave.

"Studies show that when working parents take time to be with their newborns, it's good for the entire family," Zuckerberg wrote in a Facebook post. "And I'm pretty sure the office will still be standing when I get back."

Not that Facebook has been able to avoid controversy during this charmed period.

The company has been dealing with the continued fallout of the fake news scandal that gained traction after the presidential election in November. Facebook has been taking steps to remove fake stories through a beefed up editorial group. This week, it said pages that show such stories can no longer advertise on the site.

Zuckerberg: We should explore ideas like universal basic income

In January, shortly after the election, Zuckerberg said he planned to travel to about 30 states this year to see how people are "living, working and thinking about the future." In his travels, he shook hands with people in Iowa and visited a former gold mine a mile under South Dakota. A video of that visit amassed more than 1 million views on Facebook.

He's now wealthier than anyone in tech except for Bill Gates and Jeff Bezos. Zuckerberg fashioned this life for himself by focusing on one thing for more than a decade: building an internet business.

But in a letter he and Chan wrote announcing the arrival of their daughter, Zuckerberg showed his softer side.

"The world can be a serious place," the couple wrote. "Make time to go outside and play."

As Labor Day Weekend arrives, it sounds like advice worth taking.