Is the next bubble coming?

A string of exploding investment bubbles that started with the dot-coms and ended with mortgages dominated the years from 2000 to 2009. And it looks like the next decade will be no different.

Investors who fled the last blowups risk running smack into others. The Federal Reserve is keeping borrowing costs low to help revive the economy, and that means there's still plenty of easy money around, helping traders to inflate the price of everything from stocks to commodities.

It doesn't seem to matter to many professional investors that the Standard & Poor's 500 index has turned in its first losing performance over the course of a decade or that that stocks are worth $2.5 trillion less today than when the decade began.

"They've put out the biggest punch bowl in U.S. history and people are guzzling from it," said Haag Sherman, chief investment officer at Salient Partners.

Some analysts have already been asking if the stock market formed a bubble with its huge rebound this year. The S&P 500 is up 66.7 percent from the 12-year low of 666.79. Gold is also suspect. It's above $1,098 an ounce and up 24 percent in 2009. Other possible sources of bubbles include stocks in emerging markets such as China.

With investors having $3.2 trillion in money market mutual funds that's waiting to be invested, analysts warn that bubbles may be inevitable.

Fed Chairman Ben Bernanke said last month a policy favoring cheap borrowing risked setting more traps for investors.

Analysts say the best way to avoid being caught by other bubbles is to remain vigilant about diversifying. It could also mean shedding some of the stronger performers to avoid some of the risks that the winners will falter.