Mark Zuckerberg will take two months' paternity leave later this year

• Facebook CEO Mark Zuckerberg will take two months off later this year.
• Zuckerberg's wife Priscilla Chan is expecting their second child soon.
• Facebook offers four months of paternity and maternity leave.

Priscilla Chan (R) and her husband Mark Zuckerberg announce the Chan Zuckerberg Initiative to "cure, prevent or manage all disease" by the end of the century during a news conference at UCSF Mission Bay in San Francisco.

Beck Diefenbach | Reuters

Facebook CEO Mark Zuckerberg said in an online post that he will take two months' paternity leave later this year.

Zuckerberg's wife, Priscilla Chan, is expecting the couple's second child by year's end.

"Studies show that when working parents take time to be with their newborns, it's good for the entire family," Zuckerberg said.

Chief Operating Officer Sheryl Sandberg and Chief Financial Officer David Wehner will be highest-ranking executives in his absence. He could have taken up to four months off under Facebook policy.

Facebook shares are up more than 40 percent this year, far outpacing gains in the broader market for tech stocks.

The company's market value has risen more than eightfold since it went public in May 2012, making it the fourth-most valuable U.S. tech firm.