Shares in BlackBerry Ltd. were down more than 10 per cent in early trading after the company lowered its fourth-quarter and full-year revenue expectations for its cybersecurity business.

The dip in share price comes as the company said some large deals that were expected to close in the quarter were not completed in time.

BlackBerry shares were down 67 cents at C$4.78 in trading on the Toronto Stock Exchange just before 11 a.m. ET Tuesday.

BlackBerry executive chairman and chief executive John Chen said macro challenges were a key factor for the company's cybersecurity business unit, with elongated sales cycles in government causing some large deals to slip into later quarters.

“Given the current macro backdrop, BlackBerry's management has taken proactive steps this quarter to both balance investments and manage costs to drive towards profitable growth,” Chen said in a statement.

The company, which keeps its books in U.S. dollars, also said it expects to take a one-time, non-cash charge of up to US$440 million in its fourth quarter related to its Spark security business.

In a preliminary look at its results for the quarter ended Feb. 28, BlackBerry said it expects total revenue of about US$151 million.

Revenue from its internet of things (IoT) business is expected to be about US$53 million for the quarter, while cybersecurity revenue is expected to be about US$88 million. Licensing and other revenue is expected to be approximately US$10 million.

For its full financial year, BlackBerry says it expects total revenue of about US$656 million with IoT revenue of about US$206 million and cybersecurity revenue of about US$418 million.

Licensing and other revenue for the full year is expected to be about US$32 million.

BlackBerry is scheduled to release its full financial results on March 30 when it will also provide its outlook for the year.