By TOMI KILGORE

"All for one, one for all" was the motto of the Three Musketeers, but it now also applies to the stock market.

The Dow Jones Industrial Average, the Standard & Poor's 500 Index and the Nasdaq Composite have all reached new yearly highs, and in so doing have confirmed each other's highs.

Investors like to have a good reason to justify buying, especially after the market has come so far and so long without a correction of at least 10%. But Wednesday's broad rally isn't a function of one piece of data, or belief in the overall economy's strength or even continued exceptionally low interest rates, it is a form of reverse capitulation.

Whatever the reason, equities keep rallying, and money has to follow. Like the McClellan Market Report said, when advancing stocks outnumber decliners for such an extended period it indicates there is so much money available that it needs to flow into a broad list of stocks just to find room to absorb it all.

"That's what is happening now, and it promises more upside," the McClellan Report said.

The Dow and S&P 500 hit 17-month highs in intraday trading Wednesday, while the Nasdaq reached the highest level seen in 18-months, or pre-Lehman Brothers collapse levels.

Money is moving into stocks because they are going up. The new highs in all three indexes means there is no longer a recent reference point for managers of that money to base their buying decisions. Those that have been skeptical, or underweight relative to their proxy indexes, no longer have a choice but to, at the very least, get back to neutral or risk falling further and further behind.

One reason investors may hesitate to buy at current levels is that the current string of up days -- the Dow and the S&P 500 are up 12 of the past 14 sessions, the Nasdaq has gained in 11 of 14 -- brings with it overbought technical conditions.

But while overbought conditions may lead to quick and sometimes even sharp pullbacks, they don't end a trend. If the market doesn't become overbought after such a string of gains then there would be a "negative divergence," which would warn the trend is weakening. There were some minor divergences early in the current winning streak, but those have since corrected.

There will be a pullback sooner or later. But at this point investors can no longer wait for what the market will do, they have to follow what the money is doing now.

Upside levels to keep in mind include the 11130 level for the Dow and 1225 for the S&P 500, which is about where the 200-week simple moving averages for the indexes currently come in. For the Nasdaq, 2550 was the level of a double top in mid-May and early-June 2008.

Write to Tomi Kilgore at tomi.kilgore@dowjones.com