The Globe and Mail reports in its Tuesday edition that BlackBerry stock soared after the fallen Canadian tech pioneer announced it had sold a unit that the company hoped would be a signature strategic purchase for its former chief executive officer. The Globe's Sean Silcoff writes, however, that it turned into a costly drag on the company's recovery plans. The Waterloo, Ont., company said Monday it had entered into a definitive agreement to sell its Cylance cybersecurity business to Arctic Wolf Networks Inc., an artificial-intelligence-powered cybersecurity company from Eden Prairie, Minn., for $160-million, less $40-million in certain adjustments, and 5.5 million of the buyer's common shares (all figures U.S.). Arctic Wolf will pay $80-million in cash up front when the deal closes and another $40-million a year after closing. The value of the deal is difficult to estimate, but is clearly a fraction of the $1.4-billion that BlackBerry paid for Cylance six years ago. The acquisition was the largest in BlackBerry's 40-year history and the costliest gamble during the 10-year reign of John Chen, who departed last fall. Despite divesting the unit at a steep loss, BlackBerry closed at $4.40 (Canadian), up 57 Canadian cents.