How Canada Taxes Your Options: Calls, Puts, and What They Do to Your ACB
Option premiums are not simply capital gains. Depending on how a position ends, the premium folds into your shares' cost base or proceeds, and an option written in one year and assigned in the next can require amending last year's return. Here is the full map.
Where the rules come from, and which regime you are in
Exchange-traded calls and puts in a brokerage account are governed by ITA s. 49 plus CRA's Interpretation Bulletin IT-479R. The bulletin dates from 1984 and carries an archived banner, but it remains CRA's operating guidance. The current capital gains guide still points readers to it, and the Tax Court applied its factors as recently as 2023. For most retail investors the results are capital gains and losses at the 50 percent inclusion rate, with one caution. Writing naked options is presumed to be income under the bulletin, and CRA accepts capital treatment only if you report that way consistently every year. Covered calls follow the account of the underlying shares, so a buy-and-hold investor writing calls on long-term holdings is on capital account.
One disambiguation before anything else. Options granted by your employer are a completely different regime, taxed as an employment benefit through your T4 under s. 7. This page is about the puts and calls you buy and write yourself.
The two things most guides get wrong
On exercise or assignment, the premium never stands alone. When a call you wrote is assigned, the premium is added to the proceeds of disposition of the shares called away. When a put you wrote is assigned, the premium reduces the ACB of the shares put to you. When you exercise a call you bought, the premium and strike together become the new shares' ACB. Reporting the premium as its own freestanding gain in these cases either double-taxes you or misstates the share result.
The cross-year reversal is real statute, not folklore. A premium from writing an option is a capital gain in the year you write it. If the option is exercised or assigned in a later year, s. 49(4) says the earlier year's gain must be reversed with an amended return, and the premium folded into the share transaction instead. Skip the amendment and the same premium is taxed twice. Almost no published guide covers this, and no broker slip will do it for you.
The nine outcomes on one table
| Position and outcome | Tax treatment on capital account |
|---|---|
| Buy a call, it expires worthless | Capital loss of the premium plus commission, in the year of expiry |
| Buy a call, sell it to close | Capital gain or loss against what you paid, in the year of the sale |
| Buy a call, exercise it | No gain or loss yet. Premium, strike, and commissions become the acquired shares' ACB |
| Buy a put, it expires or you sell it | Loss at expiry, or gain or loss on the closing sale, same as a call |
| Buy a put, exercise it | The premium reduces your proceeds on the shares you deliver |
| Write a call, it expires | The premium is a capital gain in the year you wrote it |
| Write a call, buy it back | The write-year gain stands and the buyback cost is a separate capital loss |
| Write a call, it is assigned | The premium is added to the proceeds of the shares sold, reversing any earlier standalone gain |
| Write a put, it is assigned | The premium reduces the ACB of the shares acquired, reversing any earlier standalone gain |
Three worked examples
Covered call assigned. You own 100 shares with a $4,000 ACB and write a $55-strike call for a $400 premium less a $5 commission. The shares are called away. Your proceeds are $5,500 for the shares, less the $5 sale commission, plus the $395 net premium, for $5,890 in total. The capital gain is $1,890 in the year of assignment, and the premium does not appear anywhere as its own gain.
Put assigned. You write a $50-strike put for a $300 premium less $5, and the shares are put to you. The 100 shares cost $5,000 plus a $5 commission, minus the $295 net premium, for an ACB of $4,710. Nothing is taxable until you sell the shares.
Call exercised. You paid $305 all-in for a call and exercise it at a $50 strike, paying $5,005 for the shares. The new lot's cost is $5,310, and if you already held 100 shares with a $4,000 ACB, the pooled ACB becomes $9,310 across 200 shares, or $46.55 each. Exercising is not a taxable event by itself.
The cross-year reversal in practice
Say you write a covered call in December 2025 for a $395 net premium and report it as a capital gain on your 2025 return. In February 2026 the call is assigned. The Income Tax Act now treats the premium as part of your 2026 share proceeds, so the 2025 gain has to come out. The formal route is a T1 adjustment to the 2025 return removing the $395, filed by the 2026 filing deadline, with the premium added to the 2026 share sale instead. If you have not yet filed the earlier return when assignment happens, simply leave the premium out of it and fold it into the share transaction directly.
Two boundaries keep this contained. A buyback does not trigger the reversal, because closing in the market is its own transaction. The write-year gain stands and the buyback cost is a loss in the year you close. And each contract is separate. If you write four puts on the same stock and only one is assigned, only that one premium moves into the shares' ACB, while the other three remain gains in their own year. Some frequent writers avoid the paperwork entirely by not writing options that expire in a future tax year.
Options and the superficial loss rule
The Act deems a right to acquire a property to be identical to that property. A call option is exactly such a right, which produces two traps around the superficial loss rule. Buying a call within 30 days of selling the underlying shares at a loss can make that loss superficial, with the denied amount added to the call's ACB. And selling shares at a loss while still holding a call on them at the end of the 61-day window can deny the loss too. Puts and written options are generally understood not to trigger the rule, since neither is a right to acquire, though that reading rests on professional commentary rather than a direct CRA ruling. One clean carve-out is confirmed. A loss from an option simply expiring is not superficial.
American rules do not apply here
A lot of options tax content online is American, and none of it transfers. Canada has no short-term versus long-term distinction, no wash-sale rule (we have the superficial loss rule, which works differently), and no equivalent of the US 60/40 treatment for index options. A Canadian on capital account has an ordinary capital gain or loss on a cash-settled index option like any other. If a page mentions Section 1256 or holding periods, it is describing someone else's tax system.
What your T5008 gets wrong about options
Option reporting is the weakest corner of the weakest slip. CRA's own rules allow Box 21 to be negative only for options and futures, which most tax software cannot even accept in its T5008 section. Written options show up with Box 20 blank or zero regardless of how the position ended. Long options that expire worthless usually generate no T5008 at all, so the loss exists only in your own records. And as of August 2026 we have not seen a Canadian broker fold an assigned option's premium into the share leg's figures.
CIBC says outright that the premium sits on its own line in the write year and that you may need to adjust when the option is exercised. Questrade warns that assigned, exercised, or expired options may not appear on the slip and tells you to keep your own records. IBKR issues a separate slip for every transaction, so the option and share legs never meet. The reconciliation is yours to do, which is the same story as Box 20 generally, only worse.
US-dollar options need two exchange rates
A US-listed option is a USD transaction, so each leg converts at the Bank of Canada rate for its own date. Write or buy on one date, and that premium converts at that day's rate. If the option is later exercised, the share transaction converts at the exercise date's rate, giving one economic position two conversion dates. The USD premium you receive or pay also flows through your USD cash pool, which can produce its own small FX gain or loss that most people never track.
Options in a TFSA or RRSP
Listed options on designated exchanges are qualified investments, and inside a registered account the premiums and gains are simply not taxed. Broker permissions are the practical limit. Registered accounts top out around Level 2 at the major Canadian brokers, which covers long calls and puts and covered calls, with cash-secured puts allowed at some brokers and spreading slowly. Naked writing and spreads need a margin account. The real risk is behavioural. Frequent, speculative option writing inside a TFSA can make the account taxable as a business, and that is not theoretical. The Tax Court upheld exactly that in a 2023 case involving a TFSA grown from $15,000 to over $600,000 through rapid trading, affirmed on appeal in 2024, and CRA has reassessed tens of millions of dollars through its TFSA audit program. Occasional covered calls are fine. Running a premium-harvesting operation in a TFSA invites a look.
How ActiveACB handles option legs
ActiveACB links your option events to their share legs automatically from your broker export. Premiums from written options are booked as gains in the write year, and when an exercise or assignment appears, the premium is folded into the share proceeds or the acquired shares' ACB the way s. 49 requires, instead of being double-counted. Expired long options become the capital losses your T5008 never reported, USD option legs convert at the Bank of Canada rate for each date, and the resulting figures land on the same Schedule 3 report as everything else. If your slip totals disagree with the calculation, the built-in T5008 checker shows the difference, and option premiums are one of the differences it explains. Run your own broker export through the ACB calculator. Your first calculation is free. The adjusted cost base guide covers the underlying rules with worked examples.
This works from any broker, not only the ones with a native parser. A trade-history CSV or XLSX brought in through the column mapper gets the same treatment: rows whose symbol is a standard option symbol (NVDA 261218C00300000, or the spaced form SPY 20MAR26 692 C) are recognized as options automatically, the per-share premium is multiplied by the contract size, and exercise, assignment, and expiry rows close the position against its pooled premium. Enter the quantity as the number of contracts, never as contracts times 100. If your export describes options in words instead of printing a symbol, tick the option-columns box in the mapping panel and point the underlying, expiry, strike, and put/call columns at it.
Frequently asked questions
Are option premiums capital gains or income?
For most retail investors on capital account, capital gains at the 50 percent inclusion rate. Writing naked options is presumed to be income under CRA's guidance, though CRA accepts capital treatment if you report that way consistently every year. Covered calls follow the account of the underlying shares.
My call expired worthless. Can I claim the loss?
Yes. The premium plus commission is a capital loss in the year of expiry. Expired long options usually generate no T5008, so claim the loss from your own records. An expiry loss is also never a superficial loss.
I was assigned on a covered call. How do I report it?
Add the net premium to the proceeds of the shares sold, and compute the gain against the shares' pooled ACB in the year of assignment. If you already reported the premium as a standalone gain in an earlier year, that year needs a T1 adjustment to remove it.
Why is Box 21 negative on my T5008?
CRA permits a negative Box 21 only for options and futures. It usually represents a written position closed at a cost. Most tax software will not accept a negative there, so the amount typically has to be handled through the capital gains section with your own figures.
I sold a put and got assigned. What is my ACB?
The strike price times the shares, plus the purchase commission, minus the net premium you received. Nothing is taxable until you sell the shares, and any earlier standalone gain reported on that premium gets reversed.
Do I pay tax when I exercise a call I bought?
No. Exercising is not a taxable event. The premium, strike, and commissions together become the ACB of the shares you acquire, pooled with any identical shares you already hold.
Does buying a call after selling the stock at a loss deny my loss?
It can. A call is a right to acquire the shares and is deemed identical property, so buying one within the 61-day superficial loss window can make the loss superficial, with the denied amount added to the call's ACB.
Do I report options traded in my TFSA?
No, gains and losses inside a TFSA are not reported or taxed. The caution is frequency. Sustained speculative option writing can cause CRA to treat the TFSA as carrying on a business and tax its income fully, an outcome the courts upheld in 2023 and 2024.