Just noticed there was a way to display an Implied Volatility column in TWS - I enabled it, but it displays nothing. So what is it for?
The IV column is for implied volatility. It will be blank for stocks (obviously). It should have a figure for option contracts (though anything really deep in the money or deep out of the money will be blank, too). The IV column will be useful for at the money and near the money stuff.
i believe you'll have to turn on the option analytics button to get the data. Also note, you have a choice to set the IV for daily or yearly IV. So if you get something like 1.6 it is daily vol => 25.6 annual.