A now-closed underground tunnel connects the Atrium to the former Toronto Coach Terminal located west, across Bay Street.

[4][5] In January 2014, H&R received a zoning variance from the Toronto City Council which would allow it to add five floors to each of the office towers, expand the ground level to enclose areas now filled by a covered arcade, planters and seating areas and create additional retail space and to redesign a media tower at the southwest corner of the structure.

[6] The Atrium houses the first Canadian location of Muji, as well as Long Tall Sally, Canada Post, Red Lobster and Rexall among other shops.

Major office tenants include the Canadian Imperial Bank of Commerce, and various arms of the Government of Ontario, including the Land Registry Office, and the Lottery Prize Claiming Centre for the Ontario Lottery and Gaming Corporation, located on ground level.

Atrium was filmed and used as a set for scenes in a shopping mall in the Canadian drama Flashpoint on the CTV Television Network.