Facebook founder Mark Zuckerberg revealed to have landed $2.3 billion stock windfall still a simple guy

Low key: Zuckerberg has been enjoying a low key holiday in Kauai with his Harvard-educated doctor wife on their latest trip to Hawaii, where they are rumoured to be on a reconnaissance trip for real estate on the island

While Mark Zuckerberg continues to enjoy his budget holiday in Hawaii, it has been revealed that the Facebook CEO is even richer than previously known after he gained $2.3 billion from exercising 60 million stock options just before the online social networking leader's initial public offering last year.

The windfall detailed in regulatory documents filed Friday also saddled Zuckerberg, 28, with a massive $1.1 billion tax bill. He raised the money to pay it by selling 30.2 million Facebook shares for $38 apiece in the IPO.

Facebook's stock hasn't closed above $38 since the IPO was completed last May. The shares gained 71 cents Friday to close at $26.85.

The 29 percent decline from Facebook's IPO price has cost Zuckerberg nearly $7 billion on paper, based on the 609.5 million shares of company stock that he owned as of March 31, according to the regulatory filing. His current stake is still worth $16.4 billion.

Zuckerberg, who started Facebook in his Harvard University dorm room in 2004, has indicated he has no immediate plans to sell more stock.

                                      Stroll: Zuckerberg and his wife laughed as they passed Shave Ice Paradise - an Obama favorite

Meanwhile the famously prudent billionaire is currently enjoying a no-frills holiday in Kauai with his Harvard-educated doctor wife on their latest trip to Hawaii, where they are rumoured to be on a reconnaissance trip for real estate on the island.

But despite being worth $13.3billion, Zuckerberg has been at pains to focus on the simple things in life rather than indulging in lavish dinners and extravagant outings.