Facebook's $19 billion bid for mobile-messaging company WhatsApp helped increase shares of BlackBerry Ltd before the opening bell today, Feb. 20, as investors placed bets that the company's own messaging platform "has been undervalued," according to Reuters.

BlackBerry shares rose 9 percent in trading after the bell on Feb. 19, as the deal increases valuation metrics around BlackBerry Messaging service.

BlackBerry Messaging, or BBM, was a ground-breaking mobile-messaging service, still used today, but its user base has not been unable to keep up with WhatsApp and other services since the Waterloo, Ontario-based had refused to open its service to users on other platforms until recently.

WhatsApp has a user base of about 450 million, a number that is increasing every day. The service works on Apple Inc's iOS platform, Google Inc's Android operating system, Apple Inc's iOS platform and devices running by both the Windows and BlackBerry operating systems.

BBM is still popular, despite the fact that sales for BlackBerry devices have declined, according to Reuters.

Blackberry finally opened the messaging platform to users of iPhones and Android devices, which has helped increase the number of its active users to over 80 million.

Shares of BlackBerry stock was up about 5.5 percent at $9.51 in trading before the morning bell today.

"Engagement metrics of BBM stack up well with WhatsApp," TD Securities analyst Scott Penner said in a note to clients, according to Reuters. "And this deal does highlight the value of messaging platforms."

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