MyCostBase follows the actual sequence investors work through when ACB gets serious: define which accounts belong in the pool, load history, inspect the calculation trail, and reconcile the year-end result before filing. The goal is not speed at any cost. The goal is to make the number defendable.
Set up the tax owner and account scope
Create the tax owner, add brokerage accounts, and mark which ones are taxable versus excluded. This is where the pooled ACB universe is defined, so the setup step matters more than a cosmetic profile screen.
Import history or enter missing events manually
Upload broker CSVs or add transactions manually for anything the import cannot supply cleanly. Buys, sells, DRIP, ROC, reinvested gains, transfers, and corrections all land in the same ledger so the history stays chronological.
Review the ledger and resolve warnings
Open the per-security ledger to inspect share count, ACB, FX rates, and realized gains row by row. If a transfer basis is missing or an assumption needs review, the warning appears before you rely on the result.
Reconcile broker figures and export the tax-year package
Compare broker or T5008 values with MyCostBase, inspect the differences, and export gains summaries, disposition detail, and security-level audit trails for filing or accountant review.
Why this workflow fits the actual ACB problem
Most ACB mistakes come from one of two places: the source history is incomplete, or the final number cannot be traced back to the rows that caused it. MyCostBase addresses both.
The setup step makes taxable scope explicit. The import step brings source rows together in one place. The ledger review step makes the calculation inspectable. The reconciliation step turns that ledger into the year-end deliverables investors and accountants actually need.
MyCostBase does not replace a trading platform and it does not replace filing software. It sits in the missing middle where adjusted cost base is usually reconstructed by hand.
What to prepare before you start
If you want a smoother onboarding pass, collect the following before creating the ledger:
- broker CSV exports for taxable accounts;
- records for transfers between brokerages;
- ETF tax slips or issuer adjustments for ROC and reinvested distributions;
- any manual FX rates or notes you already rely on.
If you want the detailed setup guidance, start with Getting Started or go straight to Importing Transactions.