Couldn't find a specific CRA reference, but this is from Malin 2009
Shares of a Bankrupt or Insolvent Corporation:
You can elect a deemed disposition of the shares for nil proceeds if the company declares bankruptcy or becomes insolvent if at the end of the tax year any of the following apply-
- the corporation is in fact insolvent
- neither the corporation or a corporation which controls it is carrying on business
- the FMV of the share is nil
- it is reasonable to expect that the corporation will not commence to carry on business
You make this election by attaching a note to your return, stating that you elect to have subsection 50(1) of the ITA apply to the said shares. If you efile, the efiler has a place to note that the letter will be sent by mail. If no note is sent, the CRA "generally" accepts the inferred election.
You are deemed to have re-acquired the shares at a nil cost, so that if they ever come back and you do sell them for $$, you must report a capital gain.