I am looking at the option chains for some of the most popular Canadian listed ETFs and stocks. I notice that most of them have a bid / ask that show zero, with occasional strike prices that show a very low (non-zero) number. At first, I thought it was because of a lack of liquidity or interest, but some of the more popular tickers show relatively high numbers on the open interest and volume columns, so that doesn't seem to make sense. Anyone familiar with options in Canada?