When placed on the Supplementary Order of Battle, a regiment is considered "virtually disbanded", and is re-formed only when the Department of National Defence deems the unit is required again.
The Supplementary Order of Battle was instituted as an alternative to outright disbandment during the army rationalizations of the 1960s.
[1] In the aftermath of the Somalia Affair in 1993, The Canadian Airborne Regiment was completely disbanded and not placed on the Supplementary Order of Battle.
On September 5, 2008, Canadian Defence Minister Peter MacKay announced that The Halifax Rifles (RCAC) would be reorganized as an active unit.
The Halifax Rifles are the first, and so far only, regiment to rejoin the Primary Reserve from the Supplementary Order of Battle.