A lot of the articles and posts I read these days ("bubbles", "overvalued", "top" etc.) remind me of what I read about Robertson's Tiger fund. A legendary hedge fund in the 90s, they got burned in the late stage of the Internet bubble by going long "value" stocks and shorting any type of grossly overvalued Internet companies. They were right of course, but not at the right time. They were killed, losing billions of dollars in those hysteric short covering rallies of 1999 and 2000 and finally capitulated on March 30, 2000 (ironically at the top of the market). Quote: "As you have heard me say on many occasions, the key to Tiger's success over the years has been a steady commitment to buying the best stocks and shorting the worst," he wrote. "In a rational environment, this strategy functions well. But in an irrational market, where earnings and price considerations take a back seat to mouse clicks and momentum, such logic, as we have learned, does not count for much." More: http://neumann.hec.ca/~p283/gpmba/Tiger.htm My take away: Even if you're the smartest guy in the world (Julian Robertson definitely was up there with other legendary investors) the market can always turn out to be smarter than you and squeeze you until you're blown out of the market. IMHO today's momentum stocks (China, the Nasdaq darlings etc.) could run way farther than many of us (myself included) can imagine. Anybody shorting these into these parabolic moves is stacking the odds against them IMO.