Your RSUs Vested, the Stock Fell, and the Tax Bill Did Not
An Ontario employee whose RSUs vested this year at $55.00 a share, and who later sold at $22.00, ended up $7,835.36 out of pocket on stock they never paid a dollar for. The tax on equity compensation is fixed the day the shares land in your account. If the price falls afterward, the loss does not erase that bill. It becomes a separate, weaker kind of loss that the tax system will not let touch it.
Why the Tax Bill Does Not Move When the Stock Does
When restricted share units vest, the value of the shares that day is added to your employment income under section 7(1)(a) of the Income Tax Act, taxed at your full marginal rate like salary. That same amount also becomes the adjusted cost base of the shares under paragraph 53(1)(j), so the shares start life already paid for, in tax terms, at whatever they were worth on delivery day.
We covered how that benefit and the cost base get set, including why the T5008 slip your broker sends can show a cost that the tax rules have already changed, in how the benefit and the cost base are set. This piece is about what happens next: what the law does once the stock falls after that cost base is locked in.
Where the Loss Dies: Section 3 of the Income Tax Act
If the shares fall below $55.00 and you sell, section 39(1)(b) turns the decline into a capital loss. Section 38(b) allows only half of it onto your return, the “allowable capital loss”. From there, whether that half survives depends entirely on how section 3 of the Income Tax Act sequences things.
Section 3 builds income in ordered steps. Paragraph 3(a) totals income from “each office, employment, business and property,” but expressly excludes a taxable capital gain; capital gains are computed separately. Paragraph 3(b) computes “the amount, if any, by which” taxable capital gains exceed allowable capital losses, and “the amount, if any” is a floor of zero: when losses exceed gains, 3(b) produces nothing, not a negative number that could reach back into 3(a). Paragraph 3(d), the one paragraph that actually subtracts losses from income, lists only “the taxpayer’s loss for the year from an office, employment, business or property or the taxpayer’s allowable business investment loss.” An allowable capital loss is not on that list. That omission is the entire mechanism: the employment income and the capital loss are computed in separate boxes, and section 3 never lets one borrow from the other.
The Ontario Employee, By the Numbers
The figures below, data as of September 22, 2026, assume an Ontario resident earning $140,000.00 who receives 2,000 RSUs vesting at $55.00 a share, holds them, then sells at $22.00.
| Line item | Amount |
|---|---|
| Employment benefit at vesting | $110,000.00 |
| 110(1)(d) deduction on the units | $0.00 |
| Adjusted cost base (53(1)(j)), $55.00 per share | $110,000.00 |
| Taxable income for the year | $250,000.00 |
| Tax on $140,000.00 alone | $36,534.68 |
| Tax on $250,000.00 | $88,370.04 |
| Tax caused by the vesting | $51,835.36 |
| Proceeds, 2,000 shares at $22.00 | $44,000.00 |
| Capital loss | $66,000.00 |
| Allowable capital loss | $33,000.00 |
| Deductible against the $110,000.00 benefit | $0.00 |
| Net cash from the whole award | -$7,835.36 |
The 110(1)(d) deduction is $0.00 because the units cost nothing, so the price test in 110(1)(d)(ii)(A) cannot be met. The companion piece linked above works through why a unit fails that test and an option does not. Everything below the ACB line is what the fall to $22.00 does: a $66,000.00 capital loss, $33,000.00 of it allowable, and $0.00 of it usable against the $110,000.00 benefit that created the tax bill.
The Break-Even Rule
The average tax rate on that $110,000.00 benefit works out to 47.12%. The break-even share price, where a sale raises just enough to cover the tax the vesting caused, is $25.92, which is 47.12% of $55.00. That match is not a coincidence: the sale only nets enough to cover the tax when proceeds equal tax owed, so break-even price divided by vesting price equals tax divided by benefit.
That generalizes: the shares can fall by 100% minus your average tax rate on the benefit before the award is worth nothing, and past that point you are paying to have been paid. Here the fall from $55.00 to $22.00 is -60.00%, well beyond the cushion a 47.12% tax rate bought.
Exercising Options Early Is Worse
Exercising options early and holding makes this worse in cash terms, because real money already left the bank before the stock fell. With a $20.00 strike, exercised at $55.00, on 2,000 shares: cash paid to exercise was $40,000.00. The benefit under 7(1)(a) is $70,000.00; the 110(1)(d) deduction is $35,000.00, so $35,000.00 lands on the return, causing $15,583.36 of tax. The ACB under 53(1)(j) is still $110,000.00, so the same fall to $22.00 produces the same $66,000.00 capital loss, stranded the same way. Net cash: $44,000.00 in proceeds, minus $40,000.00 to exercise, minus $15,583.36 of tax, comes to -$11,583.36. Exercising early and holding turns cash you had into a tax bill plus a loss you cannot use.
What to Do Instead
Selling on the vesting day would have been cleanest. That produces proceeds of $110,000.00, a capital gain of $0.00 since ACB equals the sale price, tax of $51,835.36, and net cash of $58,164.64. Against the -$7,835.36 result from holding to $22.00, that is a $66,000.00 difference, exactly the size of the loss that had nowhere to go.
A large vesting benefit that is not fully withheld at source can also push next year’s return toward quarterly instalments; the same balance-owing threshold covered in tax instalments after a large capital gain applies to a year with a big equity benefit.
Holding the shares in a registered account instead does not help. A loss realized inside a TFSA is not a capital loss for tax purposes at all, so there is nothing to carry back or forward, a point covered in our TFSA guide. The stranded loss from a regular account is at least an asset with a shelf life. Section 111(1)(b) of the Income Tax Act lets a net capital loss be deducted in “taxation years preceding and the three taxation years immediately following the year,” and the CRA’s page on capital losses confirms the same three-year carryback via Form T1A rather than an amended return: “Do not file an amended Income Tax and Benefit Return for the year you want to apply the loss.” Section 111(1.1)(a)(i) caps the deduction at the net taxable capital gain under 3(b) for that year, so the $33,000.00 allowable capital loss needs $66,000.00 of capital gains, eventually, to be fully absorbed. If it is, at the 43.41% combined Ontario marginal rate at $140,000.00 of taxable income, it is worth $14,325.17.
The One Exception: Small Business Corporation Shares
There is one route by which a loss like this reaches income generally: shares of a “small business corporation,” defined in section 248(1) as a Canadian-controlled private corporation where all or substantially all of its assets’ value is used in an active business carried on primarily in Canada. Section 39(1)(c) turns a capital loss on such a share, sold at arm’s length, into a business investment loss. Section 38(c) allows half of it, and unlike an allowable capital loss, that allowable business investment loss (ABIL) is named directly in paragraph 3(d), so it comes off income generally. The CRA’s business investment loss page puts it plainly: “If you had a business investment loss in 2025, you may be able to deduct a portion of this loss from income.” “The amount of the loss you can deduct from your income is called your allowable business investment loss (ABIL),” reported on line 21699 and deducted on line 21700.
The same $66,000.00 loss run through this route is worth far more, right away: $33,000.00 deductible against income generally is worth $16,297.97 of tax against $250,000.00 of taxable income, against $0.00 on the public company shares above until capital gains eventually appear. This assumes the same $250,000.00 of taxable income and an arm’s length sale in the same year; for a CCPC employee, section 7(1.1) defers the income inclusion to the year of disposition, so a real sale lines up the inclusion and the loss. Where a company has failed outright, subsection 50(1)(b)(iii) lets a holder elect to be treated as disposing of a worthless share for nil proceeds without a buyer, provided the corporation is insolvent, it and any corporation it controls carry on no business, the share is worth nil, and dissolution is reasonably expected.
Scope and Caveats
This covers RSUs and options, plus one narrow escape route through the business investment loss rules for arm’s length sales of private company shares. The dollar figures use Ontario rates, but section 3’s separation of capital losses from employment income is federal and applies in every province. Whether a subsection 50(1) deemed disposition also triggers the 7(1.1) disposition timing for a CCPC employee is not addressed here; no source consulted for this piece resolves it. None of this is personalized advice: a professional review of your own vesting schedule, province, and share structure is worth it before deciding whether to sell, hold, or exercise.
Disclaimer: The content on bestcanadianstocks.ca is for informational and entertainment purposes only and does not constitute financial advice. Past performance is not indicative of future results. Always consult a qualified financial advisor before making investment decisions. Income Tax Act sections 3, 38, 39, 50, 111 and 248 from Justice Laws, fetched September 22, 2026. CRA ‘Capital losses’, CRA ‘Line 25300 Net capital losses of other years’ and CRA ‘Business investment loss’ (lines 21699 and 21700), all dated 2026-02-05 and fetched September 22, 2026. Federal and Ontario 2026 brackets, basic personal amounts and the Ontario surtax from CRA ‘Current year tax rates and income brackets (2026)’ and CRA T4032ON January 2026 edition. All tax arithmetic is ours, and the rate engine is validated against Ontario’s published 53.53% top combined marginal rate before it computes anything.
