When you click the ticker to drill into the position, you can see the "Portfolio Diversity" which is the metric you're looking for.

I agree it would be helpful to include this metric on the main dashboard to see which holdings are overweight/underweight. In your screenshot, the devs could move up the # shares label so it says "Long/Short # shares @ $1.23", and then in the space where the shares are currently listed, they could put the "Portfolio Diversity" metric. Ideally, they would use the same visual indicator they have on the ticker screen (i.e. green bar filled up X%), so as you scroll through your position list you can easily differentiate your biggest positions.

Also, sorting... there's a separate feature request to allow sorting the position list, but it would be nice if we could sort by the "Portfolio Diversity" metric so the largest positions are at the top.

It is difficult to keep up with position size when we have a zillion trades executing in the background all day long. My trading program could buy/sell the same ticker 10+ times in one day -- one minute it's just a tiny little thing, the next minute it's grown. Yes, I could login to my broker to see this information, but it's a to fight with TradersPost over login credentials, and I definitely do not want to disable the brokerage connection & subscription during the trading day!