Viber's instant messaging and free Internet phone services.

The Israeli-American Shabtai family will earn some $496 million for their 55.2% stake in Israeli telecoms start-up Viber, which will be acquired by Japan’s Rakuten for $900 million, according to Israeli business daily Globes.

The Shabtai family’s holding company iMESH includes brothers Benny and Gilad Shabtai and the latter’s son, Ofer, but, Globes pointed out that most of the tax from the messaging app’s sale will not go to the Israeli government, as the Shabtais are U.S. residents.

Globes said Benny Shabtai began his career as a security officer at the Israeli embassy in Paris, then made a fortune in the U.S. by importing Raymond Weil watches from Switzerland. As investors the family has profited from positions in Israeli high-tech and defense industry firms.

Viber had not raised money from venture capital funds, with only $30 million in shareholder capital. Other shareholders include Raphael Rebhan, with a 12.5% stake through U.S. investment company IRS West, and Viber CEO and founder Talmon Marco who holds an 11.4% stake.

Last week, Hiroshi Mikitani, the Japanese billionaire who controls Rakuten, said Viber will help provide a distribution channel for his company’s digital products. Viber has more than 300 million users of its instant messaging and free Internet phone services.

The purchase of Viber is the third major takeover of an Israeli start-up company in the past year. In June 2013, Google acquired the social networking traffic app Waze for close to a billion dollars, while IBM acquired the cyber-security company Trusteer in August.