Jesse Lauriston Livermore (July 26, 1877 — November 28, 1940), also known as the Boy Plunger, was an early 20th century stock trader. He was famed for making and losing several multi-million dollar fortunes and short selling during the stock market crashes in 1907 and 1929.

There are many pearls of wisdom from this incredible trader. The following is his opinion of averaging a position.

I did precisely the wrong thing. The cotton showed me a loss and I kept it. The wheat showed me a profit and I sold it out. Of all the speculative blunders there are few greater than trying to average a losing game. Always sell what shows you a loss and keep what shows you a profit.