Rakuten to Buy Voice-Call App Maker Viber

Japanese E-Commerce Giant to Spend $900 Million on Foray Into Voice Communications
TOKYO—Japan's Rakuten Inc. 4755.TO +1.22% said it will acquire call-application maker Viber Media Inc. for $900 million, in the online retailer's first major foray into voice communications.
The deal for Cyprus-based Viber, which lets users make Internet-based calls on smartphones and
computers, expands the Japanese e-commerce giant's global portfolio of services, which now spans e-readers, financial services, and the baseball team that until recently hosted star pitcher Masahiro Tanaka.

Rakuten generates about ¥400 billion in annual revenue from its main businesses: an online shopping mall with tens of thousands of merchants, a Web-based travel service and an Internet bank. But most of its revenue and its millions of members are in Japan, where its dominance increasingly under threat by other Internet giants like Amazon.com AMZN +2.28% and Yahoo Japan. 4689.TO +3.72%

Rakuten has been trying for years to grow outside of Japan, and Viber's customer base—with 300 million users in 193 countries—is a huge pull. Founded in 2010 by Israeli entrepreneur Talmon Marco, Viber recently started an instant-messaging service for desktops allowing users to call non-Viber users' mobile phones, a move against Microsoft Corp. MSFT +0.37% -owned rival Skype.

Rakuten's recent buying spree also includes a major investment in U.S. online-scrapbooking site Pinterest in 2012 and the acquisition of Canadian e-book firm Kobo for $315 million in 2011.