What is bid size and ask size in wealth simple?

I'm new to wealthsimple app and wanted to know what some numbers mean. If we look at Microsoft stock for example and look at these numbers shown in the app:

``````Bid \$259.87 x 17,481
Last sale \$259.89 x 0
``````

I know the bid price represents the maximum price that a buyer is willing to pay for a share of stock or other security. The ask price represents the minimum price that a seller is willing to take for that same security. And Last sale is the price of the last transaction some trader did.

But what does the `17,481`, `10,387` and `0` mean? I think it relates to the bid/ask size, but not entirely sure. Does anyone know?

Thanks

• I think it's the number of lots of 100 shares. However, the "x 0" in the `Last sale` makes me doubt that. Jun 15, 2021 at 10:36
• @RonJohn I wonder if partial lots are rounded (in this case, a lot less than 50 shares would be rounded to 0). Jun 15, 2021 at 13:30
• If it is the number of lots, what does this number mean? Does it mean a person can only buy a max of 1748100 shares for example? Jun 15, 2021 at 15:39