His resignation follows the departure of several other key BlackBerry managers over the past year, including executives who ran the company's acquisition team and oversaw efforts to generate revenue by licensing its portfolio of more than 40,000 patents.

Beard, 54, played a major role in helping company Chief Executive John Chen develop a strategy for turning the company around after the collapse of its smartphone business, helping expand its line of software products for large companies and government agencies.

He oversaw marketing, strategic partnerships, developer outreach and other areas.

"That's a big loss" said Nick McQuire, vice president of enterprise research at CCS Insight, a technology consultancy. "He was very influential in BlackBerry."

Beard, whose departure was disclosed to BlackBerry staff in an internal company memo on Friday, does not intend to look for another job, said the person, who did not want to be identified because the matter is private.

BlackBerry's stock ended the session down 0.7 percent at C$13.16 on the Toronto Stock Exchange, hitting its low for the day at C$13.08 soon after Reuters reported Beard's departure.

The source did not say whether Chen intended to name a new COO. Representatives with BlackBerry did not respond to requests for comment.

McQuire said he hoped BlackBerry quickly names a successor to supervise those key functions at a time when it is looking at multiple markets in its bid to return to growth.

He said that BlackBerry should consider hiring a senior marketing executive whose role would be separate from operations.

"He had a lot on his plate, maybe they'll have to rethink the areas that Marty owned and perhaps have multiple people doing those jobs," he said.

Beard joined BlackBerry in 2014 from startup LiveOps. He previously worked for Chen at Sybase Inc, a publicly held software maker that was acquired by Germany's SAP AG.

(Reporting by Jim Finkle and Alastair Sharp in Toronto; Editing by Chris Reese, Grant McCool and Jonathan Oatis)

By Jim Finkle and Alastair Sharp