NEW YORK (CNN/Money) - The cheering for the stock market is moving from a low rumble to shout.

Any sentiment indicator you look at, it seems, shows that investors think everything is coming up roses. Investor surveys are decidedly cheery, regardless of whether the investors you're surveying are individuals or pros.

Options market indicators, like put/call ratios and the Chicago Board Options Exchange's Volatility index, show that there is very little interest buying downside protection these days. But who needs such protection, since the market is going up? According to Yale professor Robert Shiller's latest poll, 90 percent of institutional and 93 percent of individual investors believe that the stock market will be higher than it is now in 12 months time.

Meanwhile, a Securities Industry Association's annual survey shows that individual investors expect a 10 percent return in 2004.

It's the sort of stuff that sticks in the craw of James Montier, the intensely bearish global investment strategist at Dresdner Kleinwort Benson.

"10 percent equity returns? Dream on," he said. "The market isn't even vaguely priced for those returns. Everywhere I look, all I see is complacency or outright optimism."

Everywhere, that is, except corporate suites. Company insiders have been scuttling stock at a brisk pace. According to Thomson Financial, corporate executives sold $3.2 billion worth of their companies' stock last month compared with purchases of just $52 million worth of stock. That put Thomson's dollar sell-buy ratio at $59.01 -- the highest level it's been at since Thomson started tracking it.

"The corporate sector -- the guys who are supposedly in the know -- they're all selling," said Montier.

To be fair, those insider sales may not indicate that corporte executives are bearish about their companies' share prices, but rather that the long bear market taught them how dangerous it is to keep all your eggs in one basket. But this lesson of diversification appears to have been lost on many investors, who are back to buying their old favorites from 1999. And in any case, high levels of investor optimism and high levels of insider selling have historically been a dangerous mix, a sign that the market is at increased risk to some sort of selloff.

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But for now, at least, that selloff may not come. The Dow is within spitting distance of 10,000 again, and institutionally there is a strong desire to see it close the year above that mark. If that happens, there could be big inflows into mutual funds in January, as individual investors rejigger their 401(k)s, make IRA contributions, and put year-end bonus money to work.

Will they be left holding the bag? That's a 2004 story.