5 Memorable Mistakes and the Lessons I Learned

by John Deysher

As a mutual fund portfolio manager, once a year I review the stock market mistakes I made during the past year.

It’s a useful exercise. Mistakes occur for a variety of reasons including greed, fear and errors in reasoning, facts and judgment.

Once you realize you’ve made a mistake, your objective is twofold—first, to try to salvage the position and, secondly, to minimize the damage.

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John Deysher is president and portfolio manager of the Pinnacle Value Fund, a diversified, SEC-registered mutual fund specializing in the securities of small and micro-cap firms. He is a CFA charterholder and has managed equity portfolios for over 25 years. He lives and works in New York City and may be reached at


Curt from Georgia posted about 1 year ago:

Hind sight is 20:20. It always is easier to reflect on past actions and see how you could have acted differently. It is more difficult to visualize how to act when the problem/situation is out in front of you. That said, the author has made some excellent points that novice and even experienced stock investors should consider.

Harold from Missouri posted about 1 year ago:

Always be well diversified. The good part of portfolio can cushion the small percentage of mistakes.

John from Kansas posted about 1 year ago:

I would like to read more about 'thinking like a value investor' and 'thinking like a growth investor.'

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