Struggling smartphone maker BlackBerry on Monday signed a tentative deal to be acquired by a consortium led by its biggest shareholder, setting a $4.7 billion floor in the auction of the Canadian company that invented on-the-go email.

The consortium is led by Fairfax Financial Holdings Ltd, a property/casualty insurer run by Canadian investor Prem Watsa. It has offered $9 a share in cash for BlackBerry, which last week said it expected to report a quarterly loss of nearly $1 billion.

“We can deliver immediate value to shareholders, while we continue the execution of a long-term strategy in a private company with a focus on delivering superior and secure enterprise solutions to BlackBerry customers around the world,” Watsa said in a statement.

Fairfax owns almost 10 percent of BlackBerry shares.

BlackBerry has until Nov. 4 to seek superior offers, which is also the deadline for the Fairfax-led group to conduct its due diligence. Its shares, halted pending the afternoon announcement, rose to $9.20 as trade resumed but quickly slipped back to around $8.80 by mid-afternoon.

“This is a company that needs to go private if they have any chance,” said Colin Gillis, an analyst at BGC Partners. “They’d be able to restructure outside of the public eye, take a long-term view and run the company at break even.”

BlackBerry, based in Waterloo, Ontario, pioneered the concept of on-your-hip email with its first email pagers, offering secure email away from an office, and for years it was the must-have device for governments, businesses and lawyers.

But in recent years it has lost market share to the iPhone from Apple Inc. and to devices using Google Inc.’s Android operating system.

BlackBerry warned on Friday it would report revenue on the sale of just 3.7 million of its phones for the entire second quarter. By contrast, Apple sold nine million iPhone 5s and iPhone 5c models in three days after their Friday launch.

The asking price is far below BlackBerry’s share price in the heady days before the iPhone ended its dominance of mobile communications.

Even in its more recent history—littered with profit warnings, job cuts and devices that often arrived late on the scene to disinterested audiences—BlackBerry shares have only dipped below $9 briefly.

In the past 12 months the shares have risen as high as $18.32 and fallen as low as $6.22 on the Nasdaq.

BDT & Co. LLC, BofA Merrill Lynch and BMO Capital Markets are acting as financial advisors, and Shearman & Sterling LLP and McCarthy Tétrault LLP are acting as legal advisors to Fairfax in connection with the transaction.