This excerpt taken from the DVN DEF 14A filed Apr 24, 2009.
Canadian Tax Treatment
Stock Options. A participant who is granted a stock option does not have taxable income on the date of grant. Instead, tax liability is deferred until the time that the stock option is exercised. At the time of exercise, the participants are subject to tax on the difference between the value of the underlying shares acquired on the exercise of the stock option and the exercise price paid to acquire the shares. Generally, the participant will only be taxed on 50% of the difference in value. However, in certain circumstances, participants may also defer the recognition of this income until disposition of the shares. We will not be entitled to a deduction for Canadian tax purposes.
Canadian Restricted Stock Units. A participant who is granted a Canadian restricted stock unit will not have taxable income at the time of grant. Taxable income will instead occur as the participant becomes vested and shares of common stock are distributed to the participant. We will be entitled to a deduction for the payments made to the trust. However, the deduction will be deferred to the year in which the shares are vested and distributed to the participants.
Commitment Runs Deep