Most investors only think about adjusted cost base after they’ve already sold — when the decision is made, the history is scattered across two or three brokerages, and the number is harder to reconstruct than it should be.
myCostBase exists so you have that number before you need it: one running ledger of what you paid, what changed the cost, and what a sale would actually mean for your taxes. Not a bigger return — better information, and more control over what you keep after tax.
The idea behind myCostBase
Your cost base should be useful before you sell, understandable after you sell, and defensible when you file.
The missing record between your broker and your tax return
Brokerages are good at showing what happened inside their own accounts. Canadian ACB rules take a wider view.
Hold the same ETF at two brokerages, and both positions belong to one pooled cost base — not two separate ones. Add a DRIP, a return-of-capital distribution, or a broker-to-broker transfer, and the number keeps moving. No single brokerage sees that whole picture.
That’s why a T5008 cost or book value can be useful without being the ACB you actually report. The gap between those two numbers is the problem myCostBase is built to solve.
Better information at the moments that matter
Before a sale
A current ACB gives you the missing input for estimating the gain or loss a sale could create. You can compare choices with the tax consequence visible instead of discovering it after the trade settles.
While managing gains and losses
A reliable ledger helps you see which results are realized, which remain unrealized, and where a loss may need superficial-loss review. That supports tax-aware planning without turning tax considerations into investment advice.
At tax time
The same history can be reconciled against T5008 slips and exported for filing or accountant review. The year-end number remains connected to the transactions, FX rates, and adjustments that produced it.
Accuracy protects both sides of the calculation
An incorrect ACB can be wrong in either direction — understated, and you overpay tax or lose part of a real capital loss; overstated, and you underreport gains you’ll eventually have to explain.
Keeping ACB current helps you:
- see the real gain or loss before you sell;
- keep legitimate acquisition costs and adjustments in the number;
- catch when return of capital has quietly lowered an ETF’s cost base;
- avoid mistaking one broker’s book value for the complete picture;
- flag transactions that need superficial-loss or missing-data review;
- hand your accountant a traceable history instead of a single unexplained total.
Accurate records can’t make a security rise in value. They can stop tax-record errors from quietly eating into the return you already earned.
Built around Canadian taxable accounts
myCostBase focuses on the part of investing that portfolio dashboards and tax-filing software usually leave to you: maintaining the cost-base record between the day you buy and the day you sell — pooled across brokerages, converted at the right FX rate, and adjusted for every ETF distribution and corporate action along the way.
See the complete workflow or explore the ACB tracking features.
Your record should stay understandable
A final ACB without its history is difficult to verify. myCostBase keeps the calculation attached to the dated events that moved it, so you can inspect the record yourself and share useful supporting detail with a qualified professional.
Financial and tax-lot information is sensitive. Read how myCostBase approaches security and privacy, including account access, data handling, billing, and service providers.
What myCostBase does not do
myCostBase is an information, calculation, and record-keeping tool. It does not choose investments, place trades, manage a portfolio, guarantee a return, provide legal or tax advice, or file an income tax return.
The ledger can make the inputs to a decision clearer. The decision itself remains yours, and unusual transactions or uncertain tax treatment should be reviewed with a qualified Canadian tax professional.
Put your cost base to work before tax season.
Free plan includes unlimited manual entry.