I own just about every stock on the Exchange - I buy every IPO, so if I don't own it, I missed it somehow. I have 1,323 positions, worth H$1,496,386,240.07. At least that's what it was worth a few minutes ago.
It's impossible to calculate an "average" rate of return, because your rate of return depends on when you buy or short the stock, and at what price. Right now I am realizing a profit of about H$497 million, or a return of 49.83%. But I'm losing money on a chunk of those, just because I don't have time to follow all of them, and some of them will be underwater temporarily. I've had rates of return well into the four digits for individual stocks. Every other trader will have a different average rate of return.