When you open your quarterly financial statements in the next few weeks, you might be both pleased and puzzled.

Despite the economic doldrums, the stock market put together a sizzling 11 percent return over the past three months, including its best September since 1939. For a time Thursday, the Dow Jones industrial average appeared headed for 11,000.

The Dow ended the day down 47.23, or 0.4 percent, to 10,788.05. The Standard & Poor’s 500 index fell 3.53, or 0.3 percent, to 1,141.20, while the Nasdaq composite fell 7.94, or 0.3 percent, to 2,368.62.

But the recent gains are deceptive, market analysts say. While news about the economy has improved, there’s no reason to believe it’s roaring back. And the big advance was driven by a relatively small number of traders playing with a lot of money.

“I think a lot of this is just misguided optimism,” said Rob Arnott, chairman of Research Affiliates, an investment firm in Newport Beach, Calif. “The headwinds we face are pretty daunting.”

In other words, few are calling it the beginning of the next bull market — not with unemployment still near 10 percent and stocks bound in what market technicians call a trading range.

Still, the gains were impressive. In September alone, the Standard & Poor’s 500 index rose 9 percent, the Dow almost 8 percent and the Nasdaq composite index 12 percent. Every sector of the market was up.

September is usually the market’s worst month. This time it was the third-best month of any kind in 10 years, narrowly trailing only March 2003 and April 2009, when stocks were bouncing back from meltdowns.

So why the rally? Economic news, while not great, was at least enough to dispel fears of a so-called double-dip recession. The Federal Reserve indicated it was closer to taking new action to help the recovery along.

And investors started looking past the November midterm elections and concluding that likely Republican pickups in Congress mean that tax increases are less likely.

While the gains did a lot for millions of 401(k) accounts and other investment holdings, the rally was rather thin, and some market observers say that’s a sign it won’t last.

Volume on the New York Stock Exchange has been unusually low for the last several weeks. And two important sectors — financial and health care stocks — have been lagging the others, showing signs of weakness that mirror the economy.

Investors took far more money out of stock funds than they put in — more than $42 billion for the quarter and more than $15 billion in September. Meanwhile, cash has moved into bonds for 21 months in a row.

Everyday investors simply want to know whether it’s safe to get back into the market for the long haul. And that may take more than one very nice quarterly financial statement.

“Clients want to know if they’re going to be able to make it in retirement,” said Larry Rosenthal, a financial planner in Manassas, Va. “They want simplicity and they want to know that they have dependable streams of income. What I hear a lot of is ‘Are we going to be OK?’“