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’s 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 window runs from August 16 through October 15. Buy anything substantially identical during that period, and the loss is disallowed. This applies whether you buy before or after the sale.

• There is no aggregate portfolio exception. If you sell 500 shares at a loss and buy back 200 within the window, the loss on 200 is disallowed while the loss on 300 stands. The IRS looks at this share by share.
• The rule applies to options. Buying a call on the same stock within 30 days triggers a wash sale. A put that gets exercised can do the same.
• Short sales are also covered. Closing a short position at a loss and re-entering a substantially identical short within the window disallows the loss.

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 ITA 54 and denied under ITA 40(2)(g)(i). Like the US rule, it uses a 61-day window centered on the sale date.

• There is an extra condition the US version lacks: you or an affiliated person must still own the identical property at the end of the 30-day period after the sale. If you rebuy within the window but sell again before day 30, the rule technically does not apply, though the CRA may scrutinize the transaction.
• The rule covers shares, bonds, mutual fund units, and other capital property, applying broadly to most investment assets 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 has not published a bright-line definition, which leaves room for both planning and uncertainty.

Stocks in the same company are clearly substantially identical. Selling one S&P 500 index fund and buying a different one from another provider is less clear; most practitioners treat funds tracking different indexes as not substantially identical, even if they hold similar portfolios.

• Bonds from the same issuer with the same coupon, maturity, and terms are substantially identical. Different maturities or coupons generally are not. Preferred and common stock of the same company typically are not substantially identical either.
• The practical takeaway: you can usually swap one index ETF for a different one tracking a similar but not identical index. Selling a total US stock market ETF and buying an S&P 500 ETF is widely accepted as safe. Selling VOO and buying IVV (both S&P 500 trackers) is riskier 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 or exchange holds them.

• A Canadian-listed ETF and its US-listed equivalent are generally not identical property, even if they track the same index. VFV (TSX-listed S&P 500 ETF) and VOO (NYSE-listed S&P 500 ETF) are different trusts with different CUSIPs issued by different legal entities.
• This creates a planning opportunity. A Canadian resident could sell VFV at a loss and buy VOO without triggering the superficial loss rule. But if that investor also files in the US, whether VFV and VOO are “substantially identical” for wash sale purposes is 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. Selling a stock at a loss in your taxable account and buying it back in your IRA within 30 days triggers a wash sale (Rev. Rul. 2008-5). That scenario is particularly punishing: the loss is disallowed but the basis increase goes to the IRA, where it provides no benefit.

• Your IRA, your spouse’s IRA, your taxable account, and your spouse’s taxable account all need to be coordinated. DRIPs running in an IRA can inadvertently trigger wash sales on taxable-account losses.
• In Canada, the superficial loss rule applies to purchases by “affiliated persons.” Transfers to registered accounts (RRSP, TFSA) have their own stop-loss provisions under ITA 40(2)(g)(i) and ITA 40(3.4), denying the loss with different mechanics than the US IRA scenario.

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, which reaches your spouse through IRC 267(c) but generally not controlled corporations or trusts.

• 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 would not reach that corporate purchase.
• For cross-border investors holding investments through both personal accounts and a CCPC, this is a significant trap. A repurchase by either the corporation or the individual during the 61-day window triggers the rule for the other.
• Trusts where you or your spouse are majority-interest beneficiaries also count. Purchases by a family 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, so you recover it when you eventually sell the replacement (assuming you don’t trigger the rule again on the way out).

How the basis adjustment works in each country:

• US: the disallowed loss is added to the replacement shares’ basis. Buy at $50, sell at $40 ($10 loss), rebuy at $42 within 30 days: new basis is $52. The holding period of the original shares tacks on.
• Canada: the denied loss is added to the replacement’s ACB under ITA 53(1)(f). Same math, recognized when you eventually dispose without re-triggering.
• The cross-border trap: if the loss is disallowed in one country but not the other, you end up with different cost bases that create a tracking burden persisting for years.

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: sell an ETF tracking one index and buy one tracking a different but correlated index. Examples:

• Sell a total stock market ETF, buy a large-cap ETF (or vice versa). Different indexes with different constituent rules give a strong argument against identity in both countries.
• For Canadian-listed ETFs, sell one provider’s fund and buy another provider’s fund tracking a different index. Sell iShares S&P/TSX 60 (XIU), buy BMO S&P/TSX Capped Composite (ZCN). Different index, provider, and holdings.
• One caution for US persons: Canadian-listed ETFs raise a PFIC problem of their own, so check what you can hold safely before picking the swap target.

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. The two systems work very differently.

The rates that drive the math:

• US: long-term gains (held >1 year) at 0%, 15%, or 20% depending on income, plus a potential 3.8% NIIT. Short-term gains taxed as ordinary income (up to 37%). Capital losses offset gains dollar-for-dollar, plus up to $3,000 against ordinary income, with unlimited carryforward.
• Canada: only 50% of a capital gain is included in income under ITA 38(a), taxed at your marginal rate. No short-term/long-term distinction. Capital losses only offset capital gains, with indefinite carryforward or three-year carryback.
• The proposed two-thirds inclusion rate for gains above $250,000 was deferred in January 2025 and cancelled that March. The rate remains 50% at every level of gain.

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 full comparison of how each country taxes gains (inclusion rates, Section 121 vs principal residence exemption, NIIT) is in our capital gains: Canada vs the US 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.

Sources of divergence:

• US basis: your brokerage reports on Form 1099-B, but a Canadian brokerage doesn’t report to the IRS. Every purchase must be converted to USD at the acquisition-date exchange rate.
• Canadian ACB: Canadian brokerages don’t always report accurately for US-held securities. Each transaction must be converted to CAD at the Bank of Canada rate on the transaction date.
• Cross-border splits: FX conversion on different dates, wash sale or superficial loss adjustments applying in one country but not the other, and different return-of-capital rules can all cause material divergence over time.

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.

Approaches ranked by reliability:

• Swap to a similar, not identical, ETF. The workhorse strategy. Sell your losing ETF and buy one tracking a different index in the same asset class. The key is a different index, not just a different provider.
• Wait 31 calendar days. Simplest, but leaves you out of the market. Mitigate by buying a different asset class during the gap, then swap back after day 31.
• Coordinate registered and non-registered accounts. In Canada, an existing RRSP holding of the same security doesn’t trigger the superficial loss rule, but buying more in the RRSP within the window does. In the US, IRA purchases count for wash sale purposes regardless.
• Swap individual stocks. Sell one company, buy a competitor (same sector, different corporation). Sell Royal Bank, buy National Bank.
• Harvest in December, reinvest in late January. Crosses the 31-day threshold, eliminating both rules. Market-timing risk is real, but for large unrealized losses the tax savings often justify the gap. Loss harvesting is one piece of a broader year-end tax planning checklist for cross-border filers.
• Factor in FX timing. Exchange rate moves during a waiting period can create FX gains or losses that partly offset or amplify the 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 simultaneously.

A mistake creates basis mismatches that compound over time and trigger unexpected tax bills on future dispositions. The rules are technical, guidance is incomplete (especially around ETF equivalency), and the traps aren’t obvious until you’re already filing.

• Capital loss carryforward cross-border, what happens to unused losses when you move between countries

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