Wash sale vs superficial loss: cross-border guide

Tax-loss harvesting is one of the most powerful tools investors have for reducing their tax bill. You sell a losing position, lock in the capital loss, and use it to offset gains elsewhere in your portfolio. Simple enough if you file in one country. But if you’re a cross-border investor filing in both the US and Canada, you’re dealing with two anti-avoidance rules that look similar on the surface and diverge in ways that matter.

The US has the wash sale rule under IRC 1091. Canada has the superficial loss rule defined in ITA 54 and denied under ITA 40(2)(g)(i). Both exist to stop you from selling at a loss and immediately buying back the same thing. Both use a 61-day window. But they define “same thing” differently, apply to different people, and interact with registered and retirement accounts in opposite ways.

If you get this wrong, you could lose the loss deduction in one country, both countries, or create a basis mismatch that follows you for years. Here’s how both rules work, where they split, and what you can actually do about it.

What is the US wash sale rule?

The wash sale rule under IRC 1091 disallows a capital loss if you buy a “substantially identical” security within 30 days before or after the sale. The disallowed loss gets added to the cost basis of the replacement security.

The 61-day window is the key mechanic. If you sell stock at a loss on September 15, the wash sale window runs from August 16 through October 15. Buy anything substantially identical during that window, and the loss is disallowed. This applies whether you buy before or after the sale, which catches investors who pre-buy a replacement and then sell the original.

There’s no aggregate portfolio exception. Each lot matters. If you sell 500 shares at a loss and buy back 200 shares within the window, the loss on 200 shares is disallowed while the loss on 300 shares stands. The IRS looks at this on a share-by-share basis, not at the portfolio level.

The rule also applies to options. If you sell stock at a loss and buy a call option on the same stock within 30 days, that can trigger a wash sale. Writing a put option that gets exercised can create the same problem. The IRS has been clear that options on substantially identical securities count.

One point that surprises many investors: the wash sale rule applies to short sales as well. If you close a short position at a loss and re-enter a substantially identical short position within the window, the loss is disallowed under the same logic.

How does Canada’s superficial loss rule work?

Canada’s superficial loss rule denies a capital loss when you or an affiliated person sell property and reacquire “identical property” within 30 days before or after the sale, provided you still own it 30 days after. The denied loss gets added to the adjusted cost base of the replacement.

The rule is defined in the ITA 54 definition of “superficial loss” and the denial mechanism lives in ITA 40(2)(g)(i). Like the US rule, it uses a 61-day window centered on the sale date. The mechanical timing is identical to the wash sale rule.

There’s an important extra condition in Canada that the US version lacks. For the superficial loss rule to apply, the taxpayer or an affiliated person must still own the identical property at the end of the 30-day period after the sale. If you sell and rebuy within the window but then sell again before day 30 after the original sale, the rule technically doesn’t apply. In practice, the CRA may scrutinize that kind of transaction, so relying on this edge case requires careful documentation.

The superficial loss rule covers shares, bonds, mutual fund units, and other capital property. It’s broad in scope and applies to most investment assets that a cross-border investor would hold in a non-registered account.

What counts as “substantially identical” in the US?

The US wash sale rule hinges on whether the replacement security is “substantially identical” to the one sold. The IRS hasn’t published a bright-line definition, which leaves room for both planning and uncertainty.

Stocks in the same company are clearly substantially identical. If you sell 100 shares of Apple and buy back Apple, that’s a wash sale. But what about selling one S&P 500 index fund and buying a different S&P 500 index fund from another provider? The IRS hasn’t directly ruled on this for mutual funds and ETFs, and most tax practitioners take the position that funds tracking different indexes are not substantially identical, even if they hold similar portfolios.

Bonds from the same issuer with the same coupon, maturity, and terms are substantially identical. But bonds with different maturities or coupons are generally not. Preferred stock and common stock of the same company are typically not substantially identical either, since they carry different rights.

The practical takeaway for US filers: you can usually swap from one index ETF to a different one tracking a similar (but not identical) index without triggering the wash sale rule. Selling a total US stock market ETF and buying an S&P 500 ETF, for example, is widely accepted as safe. But selling VOO and buying IVV (both S&P 500 trackers) is riskier territory because they track the same index.

How does “identical property” differ in Canada?

Canada’s superficial loss rule uses “identical property” instead of “substantially identical,” and this distinction creates a different planning landscape despite sounding stricter.

Under Canadian tax law, “identical property” means property that is the same in all material respects. For publicly traded shares, this typically means shares of the same class of the same corporation. TD Bank common shares are identical to other TD Bank common shares, regardless of which brokerage account holds them or which stock exchange they trade on.

Here’s where it gets interesting for cross-border investors. A Canadian-listed ETF and its US-listed equivalent are generally not identical property in Canada, even if they track the same index. VFV (Vanguard S&P 500 Index ETF, listed on the TSX) and VOO (Vanguard S&P 500 ETF, listed on the NYSE) are different trusts with different CUSIP numbers issued by different legal entities. Most practitioners treat them as not identical for superficial loss purposes.

This creates a planning opportunity that doesn’t exist as cleanly under the US wash sale rule. A Canadian resident could sell VFV at a loss and buy VOO right away without triggering the superficial loss rule, because they’re not “identical property.” But if that same investor is also a US tax filer, they need to ask whether VFV and VOO are “substantially identical” for wash sale purposes, and that’s a closer call.

Do these rules reach across all your accounts?

Yes, and this is where many investors make costly mistakes. Both the US and Canadian rules look beyond a single brokerage account, but they do it in different ways.

In the US, the wash sale rule applies across all of your accounts. If you sell a stock at a loss in your taxable brokerage account and buy it back in your IRA within 30 days, you’ve triggered a wash sale. Rev. Rul. 2008-5 confirmed this explicitly for IRAs, and it’s particularly punishing: the loss is disallowed in the taxable account, but the basis increase goes to the IRA where it provides no tax benefit (since IRA distributions are taxed as ordinary income regardless of basis).

This means your IRA, your spouse’s IRA, your taxable account, and your spouse’s taxable account all need to be coordinated. Automatic dividend reinvestment plans (DRIPs) running in an IRA can inadvertently trigger wash sales on losses taken in a taxable account.

In Canada, the superficial loss rule applies to purchases by “affiliated persons,” which is broader in some respects. But transfers to registered accounts (RRSP, TFSA) have their own specific provisions. When you transfer a security with an accrued loss to an RRSP, the loss is denied under ITA 40(2)(g)(i), and ITA 73(1) deems the transfer to occur at the adjusted cost base. The TFSA has similar treatment under the stop-loss rules in ITA 40(3.4). The loss is denied, but unlike the US IRA scenario, the mechanics of how the denied loss gets treated differ.

Who counts as an affiliated person in Canada?

Under ITA 251.1, an affiliated person includes the taxpayer, their spouse or common-law partner, a corporation controlled by the taxpayer or their spouse, and certain trusts where the taxpayer or spouse is a majority-interest beneficiary.

This is broader than the US wash sale rule’s attribution. In the US, the wash sale rule applies to you and, through attribution rules related to IRC 267(c), to purchases by your spouse. But Canada’s affiliated person concept pulls in controlled corporations and trusts as well. If you sell shares at a loss and your holding company buys identical shares within the window, Canada denies the loss. The US wash sale rule generally wouldn’t reach that purchase by a separate corporate entity (though other provisions like the IRC 267 related-party rules might apply in certain structures).

For cross-border investors who hold investments through both personal accounts and a Canadian-controlled private corporation (CCPC), this is a significant trap. The corporation and the individual are affiliated persons, so a repurchase by either one during the 61-day window triggers the superficial loss rule for the other.

Trusts where you or your spouse are majority-interest beneficiaries also count as affiliated persons. If you’re the beneficiary of a family trust that holds investments, purchases by that trust during the window can deny your personal capital loss.

What happens to a disallowed or denied loss?

In both countries, the disallowed loss isn’t permanently gone. It gets added to the cost basis of the replacement security, which means you’ll recover it when you eventually sell the replacement (assuming you don’t trigger the rule again on the way out).

In the US, the disallowed wash sale loss is added to the cost basis of the replacement shares. If you bought stock at $50, sold it at $40 (a $10 loss), and bought it back at $42 within 30 days, your new basis is $52 ($42 purchase price plus $10 disallowed loss). Your holding period for the replacement shares also tacks on the holding period of the original shares, which matters for the short-term vs. long-term capital gains distinction.

In Canada, the denied superficial loss is added to the ACB of the replacement property under ITA 53(1)(f). The math works the same way. The loss is preserved in the higher ACB and recognized when you eventually dispose of the property without triggering the rule again.

The real problem arises when the loss is disallowed in one country but not the other. If you trigger the wash sale rule in the US but not the superficial loss rule in Canada (or vice versa), you end up with different cost bases in each country. This creates a tracking burden that can persist for years and complicates every future disposition of that security.

How do cross-border investors get caught?

The most common trap for dual filers is selling a security in one country’s brokerage and buying a similar one in the other country’s brokerage within 30 days, without realizing that one or both rules may apply.

Another common scenario involves interlisted stocks. If you sell Royal Bank of Canada (RY) on the TSX and buy Royal Bank (RY) on the NYSE within 30 days, those are the same shares of the same corporation. Both the wash sale rule and the superficial loss rule will deny the loss. The interlisted nature of many Canadian bank stocks makes this a frequent mistake.

Currency conversion adds another layer. When you sell a Canadian-dollar-denominated security and the loss includes a foreign exchange component, the FX gain or loss is a separate item for US purposes but integrated into the capital gain or loss for Canadian purposes. This can create situations where the magnitude of the loss differs between countries even before the wash sale or superficial loss rules come into play.

Can you swap ETFs to harvest losses legally?

Yes, but you need to satisfy both countries’ rules at the same time. The safest approach is swapping to a security that is neither substantially identical (US) nor identical property (Canada).

The classic strategy is selling an ETF tracking one index and buying an ETF tracking a different but correlated index. Sell a total stock market ETF and buy a large-cap ETF. Sell an S&P 500 ETF and buy a total US market ETF. These track different indexes with different constituent rules, which gives you a strong argument that they’re neither substantially identical nor identical property.

For Canadian-listed ETFs specifically, selling a fund from one provider and buying from another that tracks a different index is the cleanest swap. Sell an iShares S&P/TSX 60 ETF (XIU) and buy a BMO S&P/TSX Capped Composite ETF (ZCN), for instance. Different index, different provider, different number of holdings.

The 31-day waiting period is always an option, but it exposes you to market risk. If the security rebounds during those 31 days, you’ve missed the recovery. For volatile markets, this cost can exceed the tax benefit of the loss. The ETF swap strategy lets you stay invested in a similar market segment while satisfying both rules.

For individual stocks, swapping is harder. If you sell shares of one Canadian bank, buying shares of a different Canadian bank avoids both rules (they’re different corporations), but you’ve changed your investment exposure. That’s a trade-off between tax efficiency and portfolio alignment that each investor has to weigh.

What are the capital gains rates in each country?

The tax benefit of harvesting a loss depends on how capital gains are taxed in each country, and the two systems work very differently.

In the US, capital gains on assets held longer than one year are taxed at preferential long-term rates of 0%, 15%, or 20% depending on income, plus a potential 3.8% net investment income tax (NIIT) under IRC 1411. Short-term capital gains (assets held one year or less) are taxed as ordinary income at rates up to 37%. Capital losses offset capital gains dollar-for-dollar, and up to $3,000 of excess losses can offset ordinary income per year, with unlimited carryforward.

In Canada, only 50% of a capital gain is included in income under ITA 38(a), and that included portion is taxed at your marginal rate. There is no distinction between short-term and long-term gains. Capital losses can only offset capital gains (not other income), and unused losses carry forward indefinitely or back three years.

The federal government has proposed increasing the inclusion rate to 66.67% for capital gains exceeding $250,000 annually for individuals. This proposal has had a complicated legislative path, so confirm the current status before making large harvesting decisions. If enacted, it makes tax-loss harvesting significantly more valuable in high-gain years.

For a dual filer, a harvested loss could save you up to 23.8% on a long-term US gain (20% rate plus 3.8% NIIT) and up to roughly 27% on the Canadian side (53.53% top marginal rate times the 50% inclusion). Foreign tax credits may reduce the effective combined rate. The interaction between foreign tax credits and capital gains treatment is covered in more detail in our US-Canada tax treaty guide.

How do you track cost basis in two countries?

Tracking dual cost bases is one of the most tedious but essential parts of cross-border investing. You’ll maintain a US cost basis (in USD) and a Canadian ACB (in CAD), and they will almost certainly diverge over time.

In the US, your brokerage reports cost basis on Form 1099-B. But if you hold securities in a Canadian brokerage, that broker doesn’t report to the IRS, and you’re responsible for tracking basis yourself. Every purchase needs to be converted to USD at the exchange rate on the date of acquisition. Every sale needs the same treatment.

In Canada, you’re responsible for tracking your own ACB. Canadian brokerages don’t always report ACB accurately, especially for securities held in US accounts, and the CRA expects you to calculate it yourself. For US-dollar-denominated securities, each transaction must be converted to CAD at the Bank of Canada exchange rate on the transaction date.

The divergence between countries can come from several sources: different cost amounts due to FX conversion on different dates, wash sale or superficial loss adjustments applying in one country but not the other, and different rules for return of capital adjustments. A security you’ve held for years through multiple corporate actions can have a materially different basis in each country.

Spreadsheet tracking is the minimum. Record the date, number of shares, price per share in local currency, the exchange rate, and the resulting basis in both USD and CAD for every buy and sell. When a wash sale or superficial loss adjustment applies, note which country’s basis was adjusted and by how much.

What does a full cross-border example look like?

Let’s walk through a detailed scenario to show how these rules play out together when they both apply.

Now consider a variation: instead of buying TD on the NYSE, Marco buys shares of JPMorgan Chase (JPM). JPM is a completely different corporation. Neither the wash sale rule nor the superficial loss rule applies. The CAD $15,000 loss stands in Canada, the USD $11,250 loss stands in the US. But Marco has changed his investment exposure from a Canadian bank to a US bank, which may or may not fit his portfolio strategy.

A middle path: Marco sells TD and buys Bank of Nova Scotia (BNS). Both are Canadian banks, but they’re different corporations. No wash sale, no superficial loss. He stays in the Canadian banking sector while successfully harvesting the TD loss in both countries.

What strategies work for cross-border harvesting?

The strategies that work are the ones that satisfy both rules at the same time. Here’s what holds up in practice for dual filers.

Swap to a similar, not identical, ETF. This is the workhorse strategy. Sell your losing ETF and buy one that tracks a different index in the same asset class. Sell a Canadian S&P 500 ETF and buy a US total market ETF. Sell a Canadian bond ETF tracking the FTSE Canada Universe Bond Index and buy one tracking the Bloomberg Aggregate. The key is a different index, not just a different provider.

Wait 31 calendar days. The simplest approach, but it leaves you out of the market. You can partially mitigate this by buying into a different asset class during the waiting period (selling an equity ETF and temporarily holding a balanced fund, for instance), then swapping back after day 31.

Coordinate between registered and non-registered accounts. In Canada, be careful about RRSP and TFSA interactions with the superficial loss rule. If you sell a security at a loss in your non-registered account and the same security sits in your RRSP, you haven’t repurchased it, so the superficial loss rule isn’t triggered by the existing RRSP holding alone. But don’t buy more in the RRSP within the window. In the US, your IRA purchases count for wash sale purposes regardless.

Use individual stocks strategically. If you hold individual stocks, sell one company’s stock and buy a competitor’s. Sell Royal Bank, buy National Bank. They’re in the same sector but are different corporations, so neither rule applies. The trade-off is tracking error against your desired allocation.

Harvest in December, reinvest in late January. Year-end harvesting with a January gap is a natural approach. Sell losers in mid-December, stay in cash or a non-identical holding through mid-January, then rebuy. This crosses the 31-day threshold and eliminates both rules as a concern. The market-timing risk is real, but for positions with large unrealized losses, the tax savings often justify the gap.

Factor in FX timing. For cross-border investors, the exchange rate at the time of sale and repurchase affects both the loss amount and the future basis. If the CAD/USD rate moves significantly during your waiting period, it can create an FX gain or loss that partly offsets (or amplifies) your harvested capital loss.

Should you get professional help with this?

Cross-border tax-loss harvesting sits at the intersection of US and Canadian tax law, securities regulation, and portfolio management. Getting it right means tracking two sets of rules, two cost bases, and two currencies at the same time.

A mistake doesn’t just cost you a denied loss for one year. It creates basis mismatches that compound over time, complicate every future sale of the affected security, and can trigger unexpected tax bills when you eventually dispose of the position. For investors with significant cross-border portfolios, the cost of getting this wrong exceeds the cost of professional guidance.

The rules are technical, the guidance is incomplete (especially around ETF equivalency), and the interaction between the two countries’ regimes creates planning opportunities that don’t exist for single-country filers. But those opportunities come with traps that aren’t obvious until you’re already filing.

This guide is general information, not tax advice for your specific situation. Which points apply, and how, depends on your facts.