Does box 20 match your cost base?
Box 20 on a T5008 is your broker’s figure for what a security cost you. It is not defined to be your adjusted cost base, and on a great many slips it is not. Put both side by side, across every slip you received, and see what the difference would do to your return. It runs in your browser. Nothing you type is sent anywhere, and nothing is saved when you leave.
| Security | Box 16 qty | Box 21 proceeds | Box 20 cost | Your ACB | Outlays | Gain per the slip | Gain per your records | Remove |
|---|---|---|---|---|---|---|---|---|
| $472.50 | $1,565.44slip is lower by $1,092.94 | |||||||
| Box 20 blank | $1,100.00 |
- Proceeds
- $12,612.50
- Adjusted cost base
- $9,942.11
- Outlays and expenses
- $4.95
- Gain or loss
- $2,665.44
1 of 2 slips shows a cost that differs from your own records. 1 slip left box 20 blank, which is common and is not an error. It means the figure was never supplied, not that it is zero. The four totals above are the columns Schedule 3 asks for. This tool reports gross capital gains; the inclusion rate is applied on your return, not here.
Why the two figures differ
Box 20 is labelled cost or book value, and CRA tells the institutions issuing these slips that the amount they report there may or may not reflect the investor’s adjusted cost base. It also tells the recipient, in the guide that accompanies the slip, that determining the adjusted cost base is the taxpayer’s own responsibility. The slip is a starting point, not an answer.
The ordinary reasons the two come apart, none of which involve anyone making a mistake:
- You hold the same security at more than one institution. Adjusted cost base pools identical property across every non-registered account you hold, so no single broker can see the whole pool. Each one reports only its own share of it.
- The security was transferred in. A receiving institution knows what arrived, not what it cost. Whatever cost travelled with the transfer, if any, is the number you are now being shown.
- The fund returned capital to you. Return of capital lowers your adjusted cost base as it is paid, and a book value that was never adjusted for it sits above your real cost, which understates the gain, in your broker’s favour and against your filing.
- Distributions were reinvested. Each reinvestment is a purchase and raises the pool. It is the most commonly missed adjustment of the lot.
What this does not do
- It does not work out your adjusted cost base for you. You bring that figure; this page reconciles it. To build it from your transactions, use the adjusted cost base calculator.
- It does not apply the superficial loss rule. A loss shown here may be one you cannot claim, if you or an affiliated person bought the same security within 30 days either side of the sale.
- It does not handle a negative cost base. Return of capital reduces your adjusted cost base, and once it goes below zero the negative amount is itself a capital gain in the year it happens, separate from any sale. Enter 0 for that row here and report that gain on its own. Return of capital and your ACB covers how the base gets there.
- It does not apply the inclusion rate. These are gross capital gains, which is also what Luum’s Tax Centre reports. Your return applies the rate, and it is the one place that should.
- One currency. A disposition in a foreign currency converts at that trade date’s rate on both the cost and the proceeds. One rate applied at the end gives the wrong answer.
Educational only, and accurate to what you enter. This is not tax advice and it does not file anything. For the concepts behind it, read T5008 box 20 and your ACB. For how Luum keeps a pool across accounts, see ACB tracking.