What Questrade provides
Questrade posts your tax slips and account statements in its client centre, and lets you export transaction history for each account. For non-registered accounts you’ll generally receive a T5008 covering your dispositions, along with T3 and T5 slips for distributions and dividends. Trades inside a TFSA or RRSP aren’t reported and aren’t taxable.
Why the cost base may be incomplete
Like every broker, Questrade can only compute cost base from activity it sees in your Questrade accounts. If you transferred shares in, hold the same security at another broker, reinvested distributions, or received equity-comp shares, its cost figure can be partial or blank — while the proceeds are usually reliable.
A Questrade detail worth knowing
Questrade lets you hold US dollars, so US-denominated trades need converting to Canadian dollars at each transaction date — a common source of gains that a raw export won’t show in CAD.
Getting your data into shape
Export your Questrade activity (transactions and slips), then build a pooled cost base across all your accounts and brokers — applying reinvested distributions, return of capital, FX on US trades, and any corporate actions. That reconciled ACB, not the raw slip, is what belongs on your Schedule 3.