Quote from gnome:
Market lore is rife with stories of how some really successful player blew out. One of my favorites is about some guy who hadn't had a single losing trade in 20 years. WOW.
I followed his calls in the early '80s. His strategy was to have enough $$ in the account to handle a multiple of 5 futures contracts and to average in to overbought and oversold... playing the parameter, "the market has never extended [___] amount into overbought/oversold before".
In 1985, he started averaging into shorts. Market continued to go against him to such a degree that when he finally had to stop out, and using $100,000 as a reference:
a. 100% of all profits were lost
b. 100% of all original capital was lost
c. There was a margin call for $75,000.
In other words... after having this strategy work for 20 years, he blew everybody up in ONE trade.
I think this type of thing is a risk for the apparently super-successful. Hubris eventually makes them take ever larger risks until one time the market catches them BIG.