In general, placing an order doesn't guarantee that it will be filled. There are many reasons for why a limit order may legitimately get cancelled, but we've listed some of the more popular ones below.
1. Your limit order expired because the limit price was not met.
Whenever you submit a limit order, you must specify a limit price. For sell orders, this is the lowest price you'd be willing to sell an owned stock at, and for buy orders, this is the highest price you'd be willing to pay to purchase a stock. If the stock does not reach the limit price (or exceed it), then the order will cancel at the end of the day when markets close at 4 pm EST (or after 90 days if you selected this option).
For example, say you own stock XYZ and are interested in selling it, but the very least you want for it is $15.00 per share so you submit a limit sell order with a limit price of $15.00. The next day, XYZ had a high price of $14.90. Because it's price did not go to or above $15.00, your order would be cancelled at the end of the day.
To avoid having your limit order cancelled each day at market close, you can toggle on the option to keep the order open for 90 days when submitting it. Please note that orders that have been partially filled will get automatically cancelled when markets close.
2. Your limit order expired because there wasn't sufficient volume to fill your order.
Remember, submitting an order doesn't guarantee that it will be filled! This holds true for limit orders even if you see the limit price met. For each buyer interested in purchasing a stock at a certain price, there must be a seller interested in parting with their stock at that price as well. Since there will be only a finite number of sellers interested in parting with their shares at a particular price, this means there may not be enough for every interested buyer (the reverse can be true as well depending on demand). So, if your limit order didn't fill despite the limit price being met, the likely reason is that there just wasn't enough shares being sold at that price (or vice versa if looking to sell).
3. Your limit order expired because the limit price was not met for an odd lot.
The quotes for most securities are made based on a standardized number of units (usually 100, referred to as board lots). If you submit an order for an odd lot of shares with a limit price, your order will only be filled if the limit price meets (or exceeds) the National Best Bid or Offer (NBBO). Please note, that the NBBO may not match a specific quote provider’s data, as the NBBO takes into account all protected markets the symbol trades on, whereas a quote provider may only consider the data on one exchange.
It’s also worth noting that in Canadian markets, it is not possible to have an odd lot order partially filled. This being the case, there must also be sufficient volume available (see 2.) for the requested number of shares to have the order filled.
Note: Wealthsimple Trade does not have any control over the price at which orders are executed at.
4) You had a recent deposit get rejected by your bank.
Whenever we receive funds from a new deposit to your Trade account, your bank has about 5 business days to subsequently reject this request and pull the funds back. In this scenario, we may have previously made your funds available to trade with, allowing you to submit an order. Once we receive the rejection notice, however, the funds will be withdrawn and sent back to your bank so any outstanding orders will be cancelled.
The quickest way to tell if this is the case with your order is to check your bank account's activities to see if the funds from your deposit have been returned.