Can You Over Diversify Your Investment Portfolio?

As the saying goes, you can have too much of a good thing. This principle applies to most things in life including portfolio diversification.
When applied efficiently, portfolio diversification is a proven method for reducing overall portfolio risk exposure. However, it is possible to over-diversify investment portfolios.
In his book, One Up on Wall Street, Peter Lynch coined the term “diworsification”, which has evolved as a label for over-diversifying portfolios where too much diversification actually worsens portfolio performance.