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Why did buying at the ask cost more than the bid?

The bid is what a seller would receive. The ask is what a buyer pays. A market buy pays the ask. If the price falls after that, the loss starts from the ask, not from the bid.

Beginner guide · 8-minute read · Updated 2026-11-09

The short answer

The bid is what a seller would receive. The ask is what a buyer pays. A market buy pays the ask. If the price falls after that, the loss starts from the ask, not from the bid.

The position

Here is one position (hypothetical, made-up prices). The count is 100 shares. The first figure in the story is $20.20. The later figure is $18.

The bottom row is this account. The −$220 is the gap. The price fell. Holding does not put the first figure back. These figures are made-up, so the subtraction stays checkable after the market moves.

Start with the count. 100 shares at $20.20 comes to $2,020. The later price is $18. The same count at that price comes to $1,800. Subtract. $2,020 minus $1,800 is $220. That is the whole table. It is not a fee hiding in the price, and it is not a forecast of tomorrow.

How to check it on the statement

Read the count first. Then read the price the statement used. Multiply those two yourself. If your product is not a share, multiply the point move by the contract size instead of multiplying a share price. The number you get should match the value in the table, or you are looking at a different count.

Write the first total on one line and the later total under it. The gap is a subtraction. Do not add a second story, such as a fee or a dividend, until you see that line on the statement. A missing line is a zero, not a guess.

If you sold part of the position, split the page into the cash that left and the count that stayed. Add those two. A sale of one piece does not freeze the price of the piece you kept.

If the order never filled, the statement still shows the old count. Look in the order history for a cancel, an expiry, or a limit the market never traded. The position page will not show an order that died.

Do this before you decide what the market "meant." The dollars are the count times the price you can point at. The reason can wait until those two numbers are written down.

What happened

The bid was $20 and the ask was $20.20. A market buy of 100 shares paid the ask. That is $2,020, which is $20 more than 100 shares at the bid. The price fell to $18. The 100 shares are then worth $1,800. Nobody filled you at the bid on the way in, so the bid is not your cost.

How to read a brokerage statement shows the count you still have and the price the statement used. It does not replay the order you meant to send. If the statement's count disagrees with this page, use the statement and do the subtraction again.

What this is not

A quote screen shows one number in the middle and people treat it as the fill. The fill for a market buy is the ask. A limit buy at $20 would have waited for the bid side and might never have traded. This page is the order that did trade, at the ask, and then the price fell.

The account does not undo it

A TFSA or an RRSP changes the tax treatment of what is inside. It does not put the first price back. The shelter does not pay the gap back, and a lower price does not hand contribution room back. Room follows the contribution rules, not the chart. A taxable account shows the same mark. The wrapper decides tax. The count and the price decide the dollars.

If the custodian does not allow this product, the custodian's list wins over a general description. The math above is only for a position the account actually holds.

What to write down

1. The ask you paid, not the bid beside it.
2. The share count that actually filled.
3. The later price on the same shares.
4. That the extra twenty dollars versus the bid is inside the loss, not a separate fee.

Then subtract. If a step is missing, the gap on the screen is not explained yet. Do not fill the blank with a rate, a fee, or a yield you did not read off a statement or a contract spec.

Questions

Did I pay the bid? No. A market buy pays the ask. Here that was $20.20.

Is the twenty dollars a commission? No. It is the gap between the bid and the ask. A commission would be a separate line.

What if the ask had been the only print? Then that print is the cost. The later $18 price is a new trade, not a correction of the fill.

Does a TFSA get the bid instead? No. The shelter does not pick the bid. The fill is the fill.

Are these the live prices? No. They are hypothetical, so the −$220 stays checkable.