241.0.1. A loss incurred by a taxpayer following the disposition, at a particular time, of a share of the capital stock of a corporation that was at any time a prescribed corporation or a share of the capital stock of a taxable Canadian corporation that was held in a prescribed stock savings plan, or of a property substituted for such share is deemed to be the amount, if any, by which(a) the loss otherwise determined, exceeds
(b) the amount, if any, by which the amount of prescribed assistance that the taxpayer, or a person on with whom the taxpayer was not dealing at arm’s length, received or is entitled to receive in respect of the share exceeds any loss otherwise determined from the disposition of the share or of the property substituted for the share before the particular time by the taxpayer or the person.