851.55. In this Title,“contingent amount” , of a taxpayer at any time when the taxpayer is not a bankrupt, includes an amount to the extent that the taxpayer, or another taxpayer that does not deal at arm’s length with the taxpayer, has a right to reduce the amount at that time;
“expenditure” of a taxpayer means an expense, expenditure or outlay made or incurred by the taxpayer, or a cost or capital cost of property acquired by the taxpayer;
“option” means(a) a security that is issued or sold by a taxpayer under an agreement referred to in section 48; or
(b) an option, warrant or similar right, issued or granted by a taxpayer, giving the holder the right to acquire an interest in the taxpayer or in another taxpayer with whom the taxpayer does not, at the time the option, warrant or similar right is issued or granted, deal at arm’s length;
“right to reduce” means a right to reduce or eliminate an amount in respect of an expenditure at any time, including such a right that is contingent upon the occurrence of an event, or in any other way contingent, if it is reasonable to conclude, having regard to all the circumstances, that the right will become exercisable;
“taxpayer” includes a partnership.