Far too many people try to take investment matters into their own hands and suffer from ―poor performance-itis – a deadly wealth killing disease. This often happens from making one or several of these common mistakes:
1. Having too many portfolio holdings. Many people simply believe there is strength in numbers. You hear all the time, ―Don’t put all your eggs in one basket.While it is true you should diversify, you should be on the guard against “di-worse-ification” – having too many positions. A portfolio can be diversified having as few as ten holdings. Anything north of 50 positions can simply be too many to keep track of.

I once met a Harvard MBA who was a successful CFO for a fish company. He claimed to have ―all the answers‖ when it came to investing. When I looked at his portfolio, no lie, he owned over 250 different stocks. I asked him how he kept track of all these and his answer was simply "I don’t…" If a Harvard MBA can make this mistake, everyone else could as well.