NEW YORK (CNN/Money) - Enthusiasm for the stock market, we are constantly told, is running dangerously high, and it's hard to disagree.

The Options Volatility Index, or VIX, down at 22, suggests there isn't much worry in the options market. On the Investor Intelligence poll of stock market advisors, the percentage of bears has dropped down to 1987 levels.

Over at the Yale School of Management, the investor confidence indexes overseen by Professor Robert Shiller have all been running quite high and in some cases are at all time highs. Wall Street strategists, according to Merrill Lynch, continue to recommend investors put a hefty amount of their portfolios into stocks.

Such optimism is dangerous because it can mean that investors are already anticipating loads and loads of good news. So good news, because it is expected, doesn't power stocks higher. And bad news? When that hits it's Katie bar the door.

But when you look at what some people are doing with their money, the message on sentiment is different.

Last week the New York Stock Exchange said the number of NYSE-traded stocks sold short had risen by 2.6 percent from mid-May. Rhodes Analytics estimates that NYSE short interest came to 1.73 percent of total NYSE capitalization, up from 1.66 percent in May and near its all-time high. Plenty of people seem to be betting against the market rallying.

The stock futures market is telling a similar tale. Miller Tabak bond strategist Tony Crescenzi has pointed out that, according to the Commodity Futures Trading Commission, large speculators are holding their largest net short position in the S&P futures since December. Such traders have a reputation for being on the wrong side of any move in stocks.