Should overnight trades be avoided, and can risks be mitigated by adjusting order limit (TSX)

Question

I live in PST timezone and trade ETFs on the Toronto Stock Exchange (TSX). The market is open for me from 6:30am to 1:00pm weekdays. I'm often tempted to place orders after close, for the next opening day, because of my schedule.

Suppose I was okay buying or selling at the trade prices seen at market close (plus-or-minus some margin), is there a no-bad-surprises "safe" way of submitting an order overnight for the next opening day?

More generally, are there extra ”things”/“events” to consider when placing an order for the next day (as opposed to placing an order during trading hours)?

Relevant findings

• Investopedia: https://www.investopedia.com/ask/answers/after-hours-trading-am-i-able-to-trade-at-this-time/ . Not much substance there, just says "be careful", and warns about illiquidity.

• QTrade FAQ Q: Can I trade after hours? A: Clients can place an order at any time. If the market is closed, your order will be accepted the next business day.

• answers and comments have sparked a line of questioning about the specific threat of a stock restructure while an order is open, so i asked a specific question about this here:
  Will a pending stock buy/sell order get invalidated if the symbol or its structure changes (e.g. split)?

Answer 1

A limit order sets a price on how much you’re willing to pay for a stock, as well as the price at which you’re willing to sell your stock. That guarantees that if your order is executed, your fill will not be worse than your desired price. It doesn't matter when you place this order.

If you place a limit order to buy and the company releases bad news or the market has a bad day, taking your stock down with it, you'll buy at your limit price. That cannot be anticipated.

In the USA, corporate actions can be anticipated but there's no need worry about them because FINRA Rule 5330 requires that all open orders must be adjusted by the effect of the corporate action. I believe that it's the same for the TSX and Canada (check with your broker and/or he Canadian Securities Administrators).

For example, if you place a limit order to buy 100 shares at $50, there's a two for one split, and your order is executed post-split, then you'll pay no more than $25 for 200 shares (100 x $50 = $200 x $25). Adjustments are made for any other kind of dividend/distribution as well.

Answer 2

disclaimer: i’m the one who originally posted the question, so i can’t provide an authoritative answer on the matter (but hoping someone can throw in a comprehensive answer)

i did find an opinion from an experienced accredited investor in the litterature (in the book “Reboot your Portfolio”, on the Tricks of the Trade Chapter)

Never—and I mean never—place an order on a stock exchange when the markets are closed and expect it to get filled when they open the next day. (This is doubly true if you use a market order, but you should never do it with a limit order either.) When markets open each morning, it can take a little time for ETF prices to be updated and adjusted, so you don’t want your order to be sent a millisecond after the opening bell. Indeed, most ETF providers recommend you wait 10 or 15 minutes after the markets have opened and that you stop trading 10 or 15 minutes before they close, since pricing anomalies are most likely to occur during the first and final minutes of trading.

This is also exacerbated in two ways:

1- the holidays in US and Canada don’t line up. so you have to account for potential jumps in price on those dates

2- there is a delay between the time the order is filled and the shares show up in your account (2 days) and the day you actually own the shares officially. you won’t receive dividends for any shares you don’t own yet. the reverse is true when you’re selling shares (you still own them for 2 days after you sell them)

The other answer on this question seem true in that way too: a limit order might prevent an investor from paying too much if the stock price were to suddenly rise overnight, but it might not prevent from overpaying if the stock price were to become much cheaper overnight.

It’s almost ironic that trading platforms will let you have trades open for up to 60 days. Seems like a sure way to shoot yourself in the wallet.

(a bit of personal perspective) That said, I went through my past finances recently and noticed some transactions were performed (by my financial advisor, on my behalf) on July 4th (which is a holiday in the states, but not in canada). Not sure whether this reflects just bad judgement on their part, me just not pushing them hard enough to do the right thing, or whether in practice, in doesn’t matter that much for modest sums (~10K).