All of the optimistic signs we’ve seen from BlackBerry over the past few months all but went up in smoke on Friday after it issued a disappointing earnings report that sent shares tumbling more than 25%, stripping billions from the company’s market value. The $84 million net loss on the quarter was certainly bad enough but the number that should truly scare BlackBerry executives was the 4 million subscribers it lost despite the fact that it had just launched new devices for the first time in over a year. To make matters worse, the 4 million lost subscribers cannot be dismissed as a fluke because it’s become a trend that has only accelerated over the past three quarters.

To put things into perspective, consider that BlackBerry was still adding subscribers even during the dark days of mid-2012, when it was racking up quarterly losses in the range of hundreds of millions of dollars. But in its third fiscal quarter last year, the company’s subscriber base shrank by 1 million. In the next quarter the losses grew to 3 million and in the past quarter they swelled further to 4 million.

All told, then, BlackBerry has lost 8 million subscribers in the past three quarters. It goes without saying that this is not a sustainable trend if BlackBerry ever hopes to regain its status in the mobile world. The best-case scenario laid out by many analysts is that BlackBerry would evolve into a niche player that profitably delivered a small number of products to an adoring fan base that would never consider leaving the company for iOS or Android.

This scenario is predicated, however, on BlackBerry’s fan base either growing or at least remaining roughly the same size. The rapid loss in subscribers over the past 9 months suggests that a sizable portion of BlackBerry’s user base was itching to get out of its two-year service agreements for BlackBerry models they bought in the 2010-2011 timeframe and switch to other devices. What’s more, it doesn’t seem as though any of the company’s newest launches will draw in people who aren’t already BlackBerry diehards since both the Q10 and the Q5 were designed for smartphone users who don’t want to abandon physical keyboards.

So things look very grim for BlackBerry at the moment and investors will be looking for a big turnaround next quarter to stop the bleeding. Personally speaking, I hope that this happens because the company means so much to its millions of users and has been such an innovative force in the smartphone industry for so many years. But such a comeback will be impossible if it keeps posting awful quarters like this.