At around 1440 GMT, Blackberry shares were down 5.58 percent to 10.68 dollars, after falling 6.3 percent when the markets opened in New York.
Blackberry helped create a culture of mobile users glued to smartphones, but consumers have moved in droves to iPhones and devices using Google's Android software. The deal between Apple and IBM seemed likely to hasten the Waterloo, Ontario-based company's demise.
After posting record losses last year, Blackberry brought in new management and outsourced its handset production to Taiwan-based Foxconn.
The company said it sold 2.6 million smartphones in the last quarter. Hardware sales accounted for 39 percent of its revenues, while services grew to 54 percent. The remainder came from software and other sources.