Over that time was also a massive tech bubble. What did the S&P 500 do over that time? A tech fund? Actually, I have that answer. If you bought AAPL on Feb 25, 2008 (or thereabouts, it was the only time in the last 10 years it was around that price) you could have bought an S&P index fund at 1,222. Today, that would be a 50% unrealized gain -- not that great. BUT, were you rebalancing to your optimal portfolio, you would have been continuously selling as it rose. In the crash of 2008, you would have had no choice -- based on your optimal portfolio -- to buy a bunch more S&P, which you would have then tripled. Again, not near your AAPL number, but the risk profile of that investment is also much lower. Add the fact that you have focused on the tech sector because of your perceived knowledge, and that is why you have a higher return. But you are betting on the belief you have in these companies. There is an emotional component. I personally believe AAPL is laughably undervalued at 550, but there are lots of smart people out there -- smarter than I am -- that have much lower price targets and are actively shorting the stock. I have 5 stocks in my portfolio that I believed in -- thought they had something -- and really know the field well -- graduate degree and years of work experience well. Some have panned out, others haven't. Over the long term -- retirement length (>20-30 years) -- index funds and a balanced investment strategy is objectively better.

Also: If you bought AAPL at $35.72, your unrealized gain today is more like 1456% (based on a last trade price of 550.06).

Disclaimer: I am also at a business school, so maybe we are all just being sold the same snake oil. I sorta doubt it, though. Both of our schools are respected, and our professors are largely people who have spent a lot of time learning these lessons the hard way.