I know I can get it in a couple pull down or click menus, but I searched and searched and could not find a way to add the column vertically in my TWS portfolio page or in any new pages I create. Is it possible?
Interesting idea... and considering how closely IBKR watches/monitors Margin with every trader and in total aggregate you would think they would have already created this for IB TWS users. Stick it in their suggestion box ?
In general, there is no such thing as margin impact of a position. There is only margin of the portfolio and impact on this margin from a particular order.
Theoretically yes. In reality, however, every position has usually an independent margin impact, unless your portfolio is highly concentrated. Schwab shows margin impact in their trading app (ToS) in a column in the positions list for each position in PM margin accounts. In TWS you have to right-click on each positions and click the Show Margin Impact, which is cumbersome and you can't see your heavy margin consumers at a glance.