Toronto, Canada, December 17, 2010 — Constellation Software Inc. (“Constellation”) (TSX: CSU) announced today that it has been advised that nine of its officers, directors and executives have agreed with a brokerage firm to enter into automatic share purchase and disposition plans in accordance with applicable securities laws. The plans allow for the purchase and disposition of Constellation common shares in a systematic manner based upon pre-determined criteria. Details regarding the plans adopted by the officers and directors are contained in the table below: