Respecting the scenario where the exit tax generated on the shares of a Canadian-controlled private corporation is secured by hypothecating those shares, and there is a subsequent partial redemption of those shares, CRA stated:
On a partial redemption, the portion of the debt that is still secured by hypothec of the shares is not consistently subject to a demand for payment in full. The shares provided as security secure only the amount in question at the time of the provision of the security. If the Minister determines that, as a result of such partial surrender, the security accepted in accordance with subsection 220(4.5) is not sufficient, the Minister may request additional security within 90 days of the partial disposition of the hypothecated shares or the full payment of the debt as provided in subsection 220(4.53). The same applies to shares traded on the stock market whose market value has fallen below a certain threshold. Where additional security is provided, the Minister is deemed to have accepted it under subsection 220(4.5).