Some of Your "Income" Wasn't Income at All. It Was Your Own Money Coming Home.
Your ETF or mutual fund pays you a steady distribution, and it feels like earnings. Some of it usually is. But funds and trusts can also pay out return of capital — literally a return of your capital, a slice of your own invested money handed back to you. It isn't taxed when it arrives. That sounds like a free lunch, and it isn't: every dollar of it quietly shrinks your adjusted cost base, and the bill shows up the day you sell.
What Return of Capital Actually Is
The CRA's mutual fund guide, RC4169, lists the things a trust's distributions can be made of: capital gains, dividends, interest, other income, return of capital — or a mix. The return-of-capital part is the fund returning capital to investors rather than paying out earnings.
Here's the part people miss: you do not report return of capital as income in the year you receive it. In the CRA's own RC4169 example, the investor's $500 of return of capital is not reported as income on the return at all. Instead, it does its work behind the scenes, on your cost base.
Meet Box 42: The Quiet Line on Your T3
Return of capital from a mutual fund trust or ETF shows up in box 42 of your T3 slip, labelled "Amount resulting in cost base adjustment." Notice what's missing: there is no line on your tax return where box 42 gets entered. That's because it's not income — it's an instruction to adjust your records. The CRA's rule is simple:
- Box 42 positive amount: subtract it from the ACB of your units
- Box 42 negative amount: add it to the ACB of your units
Most years, the box 42 amount is return of capital, and it's positive — so most years, it grinds your cost base down.
Your ACB Is a Running Tab, and ROC Erodes It
Your adjusted cost base (ACB) is your investment's cost for tax purposes: what you paid, plus expenses you incurred to acquire it, such as commissions — minus any returns of capital on your units or shares, in the CRA's formula. It's the number your capital gain or loss is measured against when you sell: proceeds minus ACB (and selling costs) equals your gain or loss, reported on Schedule 3.
Every return-of-capital payment lowers that tab. Which brings us to the example that surprises people.
The Worked Example: A "Losing" Investment With a Tax Bill
- You buy $20,000 of an ETF in a non-registered account. Your ACB is $20,000.
- The ETF pays you $600 a year classified as return of capital. Over 5 years that's $3,000 back in your pocket — untaxed each year, exactly as the rules allow.
- Your ACB is now $20,000 − $3,000 = $17,000.
- You sell the whole position for $19,000.
Your account statement suggests a $1,000 loss — you put in $20,000 and got $19,000 for the units (plus $3,000 of distributions along the way). But for tax purposes, your gain is $19,000 − $17,000 = a $2,000 capital gain. There is no loss to claim. The $3,000 you received "tax-free" over the years was really an advance on your own cost base, and the gain calculation claws it back at sale time.
Ignore box 42 for a decade and this gap gets bigger every year — which is why investors who never adjust for return of capital end up either claiming losses that don't exist or understating gains, both of which the CRA can reassess.
When Your ACB Hits Zero, the Tax Arrives Early
Your ACB can't go below zero. If return of capital reduces it below zero during a tax year, the CRA treats the negative amount as a capital gain in that year — even though you sold nothing. You enter the gain on line 13200 of Schedule 3, put a zero on line 13199 (since there was no actual sale), and your ACB is deemed to be zero going forward. From then on, every further dollar of return of capital is a capital gain in the year it lands.
Don't Confuse It With Its Opposite
This is the mirror image of reinvested "phantom" distributions, which are taxed in the year they're allocated to you and push your ACB up. Return of capital is the reverse on both counts: not taxed in the year, and it pulls your ACB down. Same T3, opposite directions — mixing them up is how cost bases go wrong.
One last thing: nobody mails you an ACB slip. Your broker's "book cost" is the broker's number, not the CRA's. The running tab — purchases, reinvested distributions up, return of capital down — is yours to keep, per investment, in your non-registered accounts.
The Twikup Take
Return of capital isn't fake income and it isn't a scam — it's a deferral machine. You get cash now, untaxed, and pay later through a bigger gain (or smaller loss) when you sell. That's a perfectly good deal if you track it. Scribble each year's box 42 into a spreadsheet the day your T3 arrives, and the sale-day surprise never happens.
This article is general information about how return of capital affects adjusted cost base, not personal tax advice. Rules are as published by the CRA in guide RC4169 and its capital gains pages; your situation may differ.
Image: AI-generated illustration.