I was reading an article by David Stockman from (http://davidstockmanscontracorner.com/take-cover-now-they-dont-ring-a-bell-at-the-top/). He uses the word "short" in a way I'm unfamiliar with. If you read the paragraph below, he says "there are no shorts left." What does that mean? I understood it that when you short the market you're betting that it's going to go down. What does it mean here?
But that is the Achilles heel of the game. As the bubble takes on ever greater girth, it becomes increasingly susceptible to a negative shock to confidence. Part of the reason is technical. When markets reach their current nose bleed levels there are no shorts left; and it is also likely that the day trading gamblers have become increasingly lax about absorbing the cost of even cheap “downside insurance” (i.e. puts on the S&P 500). That is, they are “long” and “unprotected”.