Facebook made the takeover disclosure in a filing with the U.S. Securities Commission, the San Jose (Calif.) Mercury News reported. The deal involves $4 billion in cash and the transfer of more than 180 million shares of Facebook stock worth about $12 billion, the newspaper said.
Facebook is based in Menlo Park, Calif., and WhatsApp has its headquarters in Mountain View, Calif.
"WhatsApp is on a path to connect 1 billion people. The services that reach that milestone are all incredibly valuable," Facebook founder and Chief Executive Officer Mark Zuckerberg said in a release.
WhatsApp was started in 2009 by former Yahoo! executives Jan Koum and Brian Acton.
"WhatsApp's extremely high user engagement and rapid growth are driven by the simple, powerful and instantaneous messaging capabilities we provide," Koum said in Wednesday's announcement.