Many Canadian investors assume the book value displayed by their broker—or the cost figure in T5008 Box 20—is automatically their adjusted cost base. Sometimes the figures agree. Sometimes they do not.
Broker book value is still useful. It can confirm that a position has a recorded cost, help identify missing transactions, and provide a practical comparison against an independently maintained ledger. The important distinction is that a broker can calculate only from the information available to it, while a taxpayer’s ACB—and therefore the reported capital gain or loss—may depend on holdings and adjustments outside that broker’s records.
Written and researched by myCostBase. Last reviewed: September 2, 2026. Broker documentation was checked against the primary sources linked throughout this article. This article is usable independently of the product.
What broker book value means
“Book value,” “book cost,” and “average cost” can mean slightly different things in different brokerage interfaces. A practical definition is the broker’s recorded cost for the displayed position or account, using the firm’s documented method and the information in its systems.
Canadian securities rules provide a more specific starting point. National Instrument 31-103 defines book cost as the total amount paid to purchase a security, including purchase transaction charges, adjusted for reinvested distributions, returns of capital and corporate reorganizations. That regulatory definition explains what a brokerage is trying to report. It does not give one institution access to transactions, ownership facts or tax adjustments held elsewhere.
| Figure | What it usually represents | Appropriate use |
|---|---|---|
| Book cost or book value | The broker’s recorded total cost for a position, based on information available to that institution | Account reporting, performance context and reconciliation evidence |
| Average cost or average price | A per-unit display derived from the broker’s position-level cost | Comparing the broker’s per-unit figure with a separately calculated ACB per unit |
| Market value | What the position is worth at the current or reporting-date price | Measuring current value and unrealized performance—not establishing tax cost |
| Adjusted cost base (ACB) | The taxpayer’s supported Canadian tax cost after pooling identical property and applying relevant adjustments | Calculating a capital gain or loss when property is disposed of |
U.S. brokerage material often uses cost basis or adjusted cost basis for related concepts. Canadian tax reporting normally uses adjusted cost base (ACB), and the Canadian identical-property rules determine how that amount is calculated.
Depending on the broker and timing, that figure may include:
- purchases and purchase commissions recorded in the account;
- transferred book-cost information received from another institution;
- DRIP or reinvestment transactions processed by the broker;
- stock splits, consolidations, spin-offs, mergers and other corporate actions;
- annual return-of-capital or reinvested-distribution adjustments after tax factors are received.
A broker’s figure usually cannot establish:
- the pooled ACB of identical securities held at an unrelated taxable brokerage;
- the cost of transferred securities when complete history was not transmitted;
- transactions or DRIPs administered outside the brokerage;
- an adjustment or ownership fact that was never supplied to the broker.
CRA’s T5008 guide describes Box 20 as cost or book value and tells preparers to take reasonable measures to include purchase transaction charges and adjustments for reinvested distributions, return of capital and reorganizations. CRA also cautions that Box 20 may or may not reflect the investor’s ACB.
When broker book value is useful
Broker book value is especially useful for:
- Sanity-checking a ledger. A large unexplained difference can reveal a missing purchase, sale, transfer or adjustment.
- Simple single-broker holdings. A complete position acquired and maintained at one institution is more likely to agree with an independent ACB calculation.
- Identifying missing transfer data. A zero, unknown or estimated book cost is a prompt to retrieve the outgoing statement.
- Checking posting timing. Annual ETF tax adjustments may appear after year-end tax factors are received.
- Comparing systems. Agreement between the broker and an independent ledger is useful corroboration, although it is not proof that all external holdings were included.
The balanced approach is to use broker book value as evidence and a diagnostic—not to ignore it, and not to assume it is complete without reconciliation.
What adjusted cost base means and why it can differ
Adjusted cost base is generally the weighted-average cost of identical property held by the same taxpayer. If the same security is held in more than one taxable account under the same ownership, the calculation may need to pool transactions across those accounts. Canada does not generally use FIFO, LIFO or specific-lot selection for identical properties held on capital account.
For the definition and formula, see What Is Adjusted Cost Base in Canada? and How to Calculate Adjusted Cost Base in Canada.
The difference matters when securities are sold. Schedule 3 asks for proceeds, adjusted cost base and outlays or expenses. Purchase commissions generally increase ACB, while selling commissions are normally recorded as outlays or expenses. The figures used should be supported by the investor’s complete records, not selected solely because they appear on a broker screen or tax slip.
Six situations where the figures can differ
1. The same security is held at two brokerages
Suppose you buy 100 shares at Questrade for $50.00 and 50 shares at Wealthsimple for $60.00. Ignoring commissions for simplicity:
(100 × $50.00 + 50 × $60.00) ÷ 150 = $53.33 per share
Questrade may show $50.00 and Wealthsimple may show $60.00. Neither account figure alone equals the pooled $53.33 ACB. Neither brokerage can see the other’s trades.
2. Transferred book cost is missing or requires correction
A same-type in-kind transfer between taxable brokerages does not normally reset the taxpayer’s ACB. Wealthsimple and Questrade both say transferred book cost usually carries over, but each documents a process for supplying statements or correcting the value when the outgoing institution does not provide complete information.
For example, if shares with a supported ACB of $40.00 per share arrive with an unknown or estimated book value, the receiving display should be reconciled to the outgoing statement and the investor’s ledger. The issue is incomplete transfer data—not an assumption that every receiving broker resets cost to market value.
A transfer from a taxable account into a registered account such as a TFSA, RRSP, FHSA or RESP is different. Registered-plan holdings are outside the taxable ACB pool, but moving securities into a plan can still create tax consequences. For example, CRA treats an in-kind TFSA contribution as a disposition at fair market value; a gain must be reported, while a resulting loss cannot be claimed. Account-specific rules should be checked before making the transfer.
3. Annual ETF tax adjustments are posted later
Return of capital reported in T3 Box 42 generally reduces ACB. A reinvested or non-cash taxable distribution—often called a phantom distribution—can increase ACB even though no cash was received. These adjustments move cost in opposite directions, and posting practices and timing vary.
Wealthsimple says it receives annual tax factors after year-end and retroactively applies return-of-capital and non-cash distribution adjustments, generally in May. Questrade says its BK book-cost field is adjusted for corporate actions, reinvested dividends and return of capital.
An apparent difference early in tax season may therefore be a timing issue. Reconcile the year-end statement, T3 details and issuer tax information before concluding that an adjustment was omitted.
For the tax mechanics, see ETF Return of Capital and Adjusted Cost Base.
4. A DRIP occurred outside the brokerage
Some dividend reinvestment plans are administered by a transfer agent rather than the brokerage. If those purchases were never transferred into the broker’s transaction history, its displayed figure cannot include them.
The investor’s ledger should record the reinvested amount, new units and supporting statement. This is an external-data limitation, not evidence that the broker’s own DRIP processing is necessarily wrong.
5. Older records did not follow the position
Positions can pass through multiple brokerages, custodians or employer plans. A later institution may receive only a quantity, an estimated cost, or a partial history.
Do not assume the current display proves the original and adjusted cost. Preserve the earlier statements, corporate-action records, DRIPs and tax adjustments that support the position’s history. Estate transfers, spousal rollovers and other special transactions have separate rules and should be reviewed with a qualified tax professional.
6. A superficial loss adjustment is outside the broker’s view
A capital loss can be superficial when you or an affiliated person acquires the same or identical property during the period beginning 30 calendar days before the disposition and ending 30 calendar days after it, and substituted property is still owned at the end of that period. When the replacement property is held in a taxable account, the denied loss can usually be added to its ACB.
One broker may not see a replacement purchase at another institution, in a spouse’s account, through an automatic DRIP or inside a registered plan. Its book value may therefore omit the adjustment or fail to identify that the loss is denied. Review the complete rule in The Superficial Loss Rule in Canada and test a transaction with the superficial loss calculator.
Why broker book value can be higher or lower than ACB
When equivalent units are being compared, the direction of a difference often points to the missing record:
| Possible cause | Likely effect on broker value | Tax-reporting risk if used without review |
|---|---|---|
| Return of capital was not posted | Broker book value may be higher than supported ACB | Capital gain may be understated or capital loss overstated |
| Non-cash reinvested or phantom distribution was not posted | Broker book value may be lower than supported ACB | Capital gain may be overstated or capital loss understated |
| Superficial-loss ACB addition was not posted | Broker book value may be lower than supported ACB | The taxpayer may report too much gain or too little loss |
| Purchase or DRIP occurred outside the broker | The pooled per-unit difference can move in either direction | The share count and total cost must be reconciled before comparing per-unit figures |
| Transfer history is missing or estimated | Difference can move in either direction | The displayed figure may have no reliable relationship to historical ACB |
| Identical property is held at another taxable brokerage | Difference can move in either direction | The account-level figure does not represent the taxpayer’s pooled ACB per unit |
Do not force an independent ledger to match the broker. Reconcile the difference to source documents, ask the broker to correct missing transfer information where appropriate, and preserve both the original statement and any correction confirmation.
What the brokerages document
The table below reports what the firms’ own documentation said when checked on August 28, 2026. Interfaces and procedures can change, so the linked source should control if a later version differs.
| Brokerage | What its documentation says | What still requires investor review |
|---|---|---|
| Wealthsimple | Its ACB guidance says book value is eventually adjusted for return of capital and reinvested distributions after annual tax factors arrive. Its transfer guidance says book cost transfers automatically in most cases and can be updated from an outgoing statement when it does not. | Identical securities at another institution; omitted external history; whether a year-end adjustment has been posted yet. |
| Questrade | Its reports guide says BK book cost includes corporate actions, reinvested dividends and return of capital. Codes such as HMV, HMVD and ND identify estimated or unavailable values. Its transfer guide says book cost usually transfers and can be corrected with a statement. | Holdings at another institution; any value marked estimated or unavailable; source documents supporting a correction. |
| Interactive Brokers | Its Open Positions guide shows average cost and cost basis. Its Trades guide reports cost basis, FX-to-base amounts and mark-to-market performance as separate fields. IBKR Canada documents Canadian T3, T5 and T5008 reporting. | Cross-broker pooling; transaction-level CAD conversion; Canadian tax adjustments not established by the cited reports; confirmation of how fees appear on the T5008. |
A note about foreign-currency holdings
Canadian capital gains and losses are reported in Canadian dollars. Purchase cost and sale proceeds should be converted separately using the relevant rate for each transaction.
CRA’s foreign-currency folio identifies the Bank of Canada rate as an accepted source. It also says another independent, market-recognized and verifiable source may be accepted when it is used consistently and meets CRA’s stated conditions. The issue is therefore not that an IBKR conversion is automatically unacceptable; it is whether the rate source and transaction-level calculation meet the Canadian reporting requirements and are documented.
See USD Stocks in Canada: How FX Conversion Affects Capital Gains for the detailed workflow.
T5008 Box 20: useful cross-check, not automatic proof
Box 20 contains the T5008 preparer’s cost or book value. CRA says it may or may not reflect the investor’s ACB, and the investor is responsible for making the adjustments needed for tax reporting.
Box 20 is more likely to be a useful cross-check when:
- the complete history is at one institution;
- there were no unresolved transfers or external transactions;
- annual adjustments and corporate actions have been posted;
- there are no identical holdings at another taxable brokerage.
Even then, compare it with the trade confirmation and ledger. For the full T5008-to-Schedule-3 workflow, see T5008 Box 20 vs Adjusted Cost Base.
Importing a T5008 through CRA Auto-fill My Return, Wealthsimple Tax, TurboTax or another filing product does not validate Box 20. Auto-fill transfers information CRA has on file into the tax software; the investor still needs to reconcile the imported cost or book value with a complete ACB ledger and make supported adjustments before filing.
Practical reconciliation workflow
For each security sold:
- Reconcile the share quantity to year-end and transaction statements.
- Search every taxable account under the same ownership for identical property.
- Verify transferred cost against the outgoing statement.
- Check DRIPs, stock splits and other corporate actions, T3 Box 42, phantom distributions and issuer tax-character information.
- Convert each foreign-currency transaction to Canadian dollars using a documented rate source.
- Review purchases by affiliated persons and accounts that could trigger the superficial loss rule.
- Compare the resulting ACB for the units sold with T5008 Box 20.
- Separate purchase commissions included in ACB from selling commissions reported as outlays or expenses.
- Record the reason for any difference and use the supported figures on Schedule 3.
The T5008 ACB reconciliation checker can compare two figures. The Canadian Adjusted Cost Base Checklist provides the complete source-document and accountant-handoff workflow. For detailed pooling, see Pooled ACB Across Multiple Brokerages.
Sources and update policy
Tax explanations on this page are grounded in the primary CRA and Income Tax Act sources linked in context. Brokerage descriptions link directly to the documentation supporting each statement rather than repeating the same links in a separate bibliography.
Broker-specific statements should be rechecked at least annually and whenever a brokerage materially changes its reporting documentation. Corrections can be reported through the myCostBase contact page.
If you prefer dedicated software, myCostBase can maintain a pooled ledger across taxable accounts, recalculate ACB when recorded transactions and adjustments change, and compare your supported ACB with T5008 values. A spreadsheet or a tax professional may also be appropriate, depending on the portfolio. Create a free account →
Scope: This article assumes the securities are held on capital account. Securities held as inventory in a trading business, as well as short sales, derivatives and unusual reorganizations, can require different treatment.
Frequently asked questions
Is my broker’s book value the same as my adjusted cost base?
Not necessarily. Broker book value can be a useful cross-check and may agree with adjusted cost base in a simple, complete single-broker history. It may not include identical securities held at another taxable brokerage, missing transfer history, or adjustments the broker has not yet received or posted.
Why does Wealthsimple’s book value differ from my ACB?
A difference can arise because Wealthsimple cannot see identical securities held at another institution, because transferred cost information is missing, or because annual ETF tax adjustments have not yet been posted. Wealthsimple says it applies return-of-capital and reinvested-distribution adjustments retroactively after receiving annual tax factors.
Can I use the T5008 Box 20 figure from Questrade as my ACB?
Treat it as a cross-check, not automatic proof of your complete ACB. Questrade says its BK book-cost field includes corporate actions, reinvested dividends and return of capital, but it cannot include holdings at another institution or information it never received. CRA says Box 20 may or may not reflect the investor’s ACB.
Does Interactive Brokers calculate my adjusted cost base for Canada?
Interactive Brokers reports average cost and cost-basis information, but those figures are not proof of a taxpayer’s complete Canadian ACB. They cannot account for identical properties held at another brokerage or facts not supplied to IBKR. Canadian investors should reconcile the reports to their complete records and document the Canadian-dollar exchange rates used.
Can broker book value be higher or lower than adjusted cost base?
It can be either. Missing return-of-capital adjustments can leave broker book value higher than supported ACB, while missing non-cash reinvested distributions or superficial-loss additions can leave it lower. Transfers, DRIPs, external purchases and cross-brokerage pooling can move the per-unit difference in either direction.
Does importing a T5008 into tax software verify Box 20?
No. Auto-fill and tax software can import the T5008 information available from CRA, but importing the slip does not verify that Box 20 equals your complete adjusted cost base. Reconcile the imported amount to your transaction history and make supported adjustments before filing.
General information only — not tax, legal, or financial advice. Consult a qualified professional for advice specific to your situation.