Facebook Inc (NASDAQ:FB) announced that it entered a definitive agreement to acquire WhatsApp, a rapidly growing cross-platform mobile messaging company for approximately $19 billion in cash and stock.

According to the social network giant, the acquisition price is composed of $4 billion cash and approximately $12 billion worth of shares of Facebook Inc (NASDAQ:FB). The company said the transaction also provides for an additional $3 billion in restricted stock units, which will be granted to the founders and employees of WhatsApp. The restricted stock units will vest over four years following the closing of the deal.

In a statement, Mark Zuckerberg, chief executive officer of Facebook Inc (NASDAQ:FB) said,”WhatsApp is on a path to connect 1 billion people. The services that reach that milestone are all incredibly valuable. I’ve known Jan for a long time and I’m excited to partner with him and his team to make the world more open and connected.”

On the other hand, Jan Koum, co-founder and CEO of WhatsApp said, “WhatsApp’s extremely high user engagement and rapid growth are driven by the simple, powerful and instantaneous messaging capabilities we provide. We’re excited and honored to partner with Mark and Facebook as we continue to bring our product to more people around the world.”

WhatsApp has more than 450 million monthly users and 70% are active on a given day. The company continues to experience strong growth and it is adding more than 1 million registered users per day. Its messaging volume reaches almost the entire global telecom SMS volume.

According to Facebook Inc (NASDAQ:FB), all the outstanding shares of WhatsApp capital stock and options to purchase its WhatsApp capital stock will be cancelled in exchange for $4 billion in cash and 183,865,778 shares of Facebook Class A common stock . The founder and employees of WhatsApp will also receive 45,966,444 restricted stock units after the closing of the transaction.

Facebook Inc (NASDAQ:FB) will pay WhatsApp $1 billion cash and issue $1 billion worth of shares of Class A common stock of Facebook in the event of termination of the merger agreement under certain circumstances primarily due to a failure to obtain regulatory approvals.