Garda is working with investment banks Bank of America Corp (>> Bank of America Corp), Jefferies LLC and Royal Bank of Canada (>> Royal Bank of Canada) and is in talks with a small number of private equity firms about a potential deal, according to the people.

Montreal-based Garda is owned by private equity firm Apax Partners LLP and its founder Stéphan Crétier, which together took the company private in 2012 for C$1.1 billion ($850 million), including the assumption of debt. Crétier plans to keep at least some of his equity in the company, one of the people said.

The sources asked not to be identified because the sale process is confidential. Apax, Bank of America, Jefferies and Royal Bank of Canada declined to comment. Garda had no immediate comment.

Garda is the world's largest privately owned security company, according to its website. It helps businesses transfer cash, provides services such as pre-board screening at airports and risk consulting services. It had revenue in the 12 months ending April 30 of C$1.9 billion, according to Moody's rating agency.

Private equity firms have homed in on the security sector as the U.S. economy improves, with Warburg Pincus investing an undisclosed amount in Universal Services of America last month and French buyout firm Wendel (>> WENDEL) buying U.S. security firm AlliedBarton for $1.67 billion from Blackstone (>> Blackstone Group LP) in June.

(This version of the story corrects Garda founder's name to Cretier instead of Cretie in paragraph three)

(Reporting by Mike Stone and Greg Roumeliotis in New York; Editing by Carmel Crimmins and Matthew Lewis)

By Mike Stone and Greg Roumeliotis