MyCostBase is built around one job: maintain a reviewable adjusted cost base ledger for Canadian taxable accounts. It keeps the full transaction trail, calculates the numbers that change with each event, and surfaces warnings when the available data is not complete enough to trust silently.
One pooled adjusted cost base across all taxable brokerage accounts
Canadian ACB rules apply across the tax owner’s non-registered accounts, not per brokerage login. MyCostBase combines holdings for the same identical property into one weighted-average ACB pool — so a buy at Questrade and a sell at Wealthsimple still roll into the same ledger, exactly as CRA requires.
Registered accounts (RRSP, TFSA, FHSA, and RESP) stay outside the pool. That classification happens at account setup because it changes the legal calculation, not just the display.
Why this matters: If you report a capital gain using only the selling broker’s book value, you may be overstating or understating your gain. The correct ACB must reflect every purchase, transfer, and adjustment across all taxable accounts for that security.
Import from your Canadian broker or enter history manually
MyCostBase supports the transaction types that investors need to maintain an accurate ledger over time:
- buys and sells with full commission tracking;
- DRIP share purchases;
- return of capital (ROC) adjustments from T3 and T5 slips;
- reinvested capital gain distributions;
- stock splits;
- broker-to-broker transfers with original cost basis carried forward;
- manual corrections with a required explanatory note.
For CSV imports, the system flags duplicate rows, unrecognized securities, missing Bank of Canada FX rates, and transfers where the original cost basis is not yet known. That keeps the ledger accurate instead of quietly absorbing bad source data.
Automatic Bank of Canada FX conversion for USD and foreign-currency trades
Foreign-currency trades must be converted to CAD using the exchange rate on the transaction date — not a flat annual average. MyCostBase fetches Bank of Canada daily rates for each transaction, records the rate source alongside the row, and handles weekends and holidays consistently.
If you need to use a different documented rate (for example, from a bank statement), you can override it and the note becomes part of the audit trail rather than an off-platform fix no one can trace later.
Per-security ledger with running ACB, share count, and gain-or-loss history
Every security has a chronological ledger showing the running share count, total ACB, ACB per share, and realized gain or loss after each event. The goal is not just to output the final number — it is to let you inspect where that number came from.
That matters when you need to answer questions like:
- why ACB dropped after an ETF return-of-capital slip;
- which broker transfer carried the original cost basis forward;
- which Bank of Canada FX rate was applied to a USD sale;
- whether a manual adjustment occurred before or after a disposition.
Warnings before you file — not after a CRA letter arrives
MyCostBase does not present a clean-looking number when the data behind it is incomplete. If a transfer cost basis is missing, a security needs confirmation, or a superficial loss scenario may require manual review, the product surfaces the warning directly.
This matters most in cross-account histories where the risk is not a calculation bug — the risk is assuming source data was complete when it was not.
T5008 reconciliation and export for accountants and tax software
The year-end workflow is built around the actual handoff Canadian investors need before filing:
- compare broker or T5008 figures against MyCostBase ACB;
- inspect the difference at the security level;
- explain likely causes (missing ETF adjustments, pooled cross-brokerage holdings, transfer cost basis errors);
- export capital gains summaries, disposition detail, and full audit trails.
MyCostBase does not replace tax filing software like TurboTax or StudioTax. It supplies the upstream ACB and gain/loss work those filing tools still expect you to have already done correctly.
Built for Canadian investors with non-registered accounts across multiple brokerages
The product is the right fit when you hold stocks or ETFs in one or more taxable accounts and need more than a single broker’s book value column. It is especially useful if you have:
- the same ETF or stock held at two or more Canadian brokerages;
- USD-denominated positions requiring daily Bank of Canada FX conversion;
- ETF distributions (ROC, DRIP, reinvested gains) that change your ACB annually;
- broker-to-broker transfers where cost basis continuity matters;
- year-end T5008 mismatches that need a clear explanation before filing.
If you want the step-by-step workflow, read How It Works. For implementation detail, start with Getting Started and Importing Transactions.