Retail investors have begun to take the driver's seat in Wall Street's aggressive rally, an indication both that the surge could have some life yet and that it's likely nearing an end.

Mutual funds — the vehicles through which most mom-and-pop investors play the stock market — had lost funds for nine consecutive months heading into February.

But over the past several weeks the tide has turned.

Stock funds have seen inflows in three of the past four weeks, with another $1.04 billion coming in for the week ending Feb. 15, according to the most recent data from the Investment Company Institute. Unless there is a major shift in allocation, February is shaping up as a solidly positive month for stock fund inflows.

Trouble is, the last time retail investors didn't take more out of their funds than they put in was last April, which saw inflows of about $6 billion.

That move coincided with the end of a stock market rally that looked much like the current one — a big surge higher as the year began that preceded an ugly six-month skid that made sell-in-May-and-go-away the trade of the year in 2011.

What's more, institutional investors — often referred to as part of the "smart money" in the market because of their insider position — have been slowly heading for the exits.

After pulling about $100 million from zero-yielding money market funds in 2011, the folks with the deep pockets are heading back toward the sidelines. Institutional deposits have increased by $9 million in February — a relatively miniscule amount, to be sure, compared to a total of $1.74 trillion on hand, but a number that's been steadily rising.

Finally, corporate insiders are taking an increasingly cautious approach as well.

They've dumped $4.2 billion in stock this month, about double January's level and — here's that warning sign again — the most since May 2011 as last year's rally fizzled, according to TrimTabs.

Company stock buybacks, meanwhile, are at a healthy $2.1 billion daily level, but are mainly concentrated among a few big purchasers. The number of daily buyback announcements is at its lowest level since the October to November period of 2009.

"The best-informed market participants — the top insiders who run U.S. public companies — are taking full advantage of the stock market melt-up to unload huge amounts of shares," TrimTabs said in its weekly market analysis.

The fear here is an important one — that retail investors will be the last ones to the party, buying high and selling low as the smart-money guys get out when the getting's good.

"One thing we know is money goes to where it's best treated," says Quincy Krosby, chief market strategist at Prudential Annuities in Newark, N.J.

"The fact is, if the market keeps moving higher without volatility pushing the market down dramatically or upward dramatically, you're going to see retail investors put money into equities," she adds. "But what about the professional traders who take advantage of that?"

Continued inflows of retail money might push those who have been in the market to start cashing out as the late money drives up prices.

Insiders are considered the smart money, Krosby says, because of "the notion that they know more."

"The classic rationale for insider selling at the stage we're in now is they know more than the average investor regarding the company's guidance," she adds.

The bright side: Those institutional outflows could represent simple profit-taking and an anticipation that a modest correction is in the cards.

Standard & Poor's strategist Sam Stovall sees resistance for the "500" in the 1360 to 1370 range, where a pullback of 5 percent or so is likely, sending the average down in the 1270 or so range. For the full year, he expects the S&P to hit 1400, which would constitute a 9 percent or so run from the pullback levels.

In other words, a pullback here could make an attractive entry point, and retail investors might be better off waiting it out.

"March and April tend to be favorable in terms of seasonality," Krosby notes. "If we do have a pullback, I think it brings in more buyers."

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