CAD
COLONIAL COAL INTERNATIONAL CO
stock CVE

CAD about to breach below 0.7 USD.

I would suggest to you to do your own study from real data.
First log into your bank account and do a transfer from $10,000 usd to cad and see what exchange rate they are using. Write it down. Cancel the transaction.
Second, log into your brokerage account and do a currency exchange from $10,000 usd to cad. Write it down. Cancel the transaction.
Third, in your brokerage account, look at your US holdings and see how much CAD they are valued. Write down the effective exchange rate they are using. In BMO Investorline, your USD holdings (stocks and cash) are stated in both USD and CAD. Write down the exchange rate they are using.
Fourth, go to Yahoo Finance and look at the latest stock price for
TD & TD.TO
RY & RY.TO (and other Canadian banks)
ENB & ENB.TO
BCE & BCE.TO
and any other Canadian stock you know that's also traded in USD.
Calculate all the exchange rates of each of these stocks.
Finally, in Yahoo Finance, look for the latest price of the CAD in USD.
Norbert's Gambit is item 4 of the above. It'll be the best rate you'll be able to achieve. If you're lucky, the stock price will increase when you sell and make a small capital gain.

A couple of good options are:
\- equal-weight S&P 500 ETF like RSP (or EQL in CAD)
\- small-cap value ETFs like AVUV and AVDV

So you simply sell your CAD dual listed holding in USD and accept the FX exchange rate?

I've been with them since trading commissions were $25.
I'm not a complicated investor. Strictly stocks, some trading, mostly buy and hold.
I also have accounts with National Bank Direct Brokerage and WealthSimple. My son has accounts with TD Direct Brokerage where you can buy or reinvest fractional shares.
Every platform has its pros and cons. You just have to know the characteristics of each one and adapt.
The zero commission at BMO Investorline should be huge especially for those who do Norbert's Gambit to exchange currency between CAD and USD.