Then came the credit crisis, which erupted exactly four years ago. By the end of 2008, holdings in mutual funds were down to $9.6 trillion, a drop of 20.0%.
Skip forward to September 2012. Mutual funds have surpassed their pre-crisis favor with investors.
Overall, institutions and individuals had placed $12.3 trillion in mutual funds by the end of July, up 6.0% from $11.6 trillion at the end of 2011.
There is one black spot. Since the end of August 2008, $427.5 billion has been pulled out of funds that invest long-term in U.S.-based stocks.
But that much money and more has gone into bond funds, even with bonds paying historically low rates of interest. In that same period, $891.7 billion has gone into all forms of bond funds.
Ten mutual funds identified by Morningstar for Money Management Executive have, in fact, achieved 17.1% annualized returns or better, in this four-year comeback period.
The biggest winners have not been in bond funds.
Funds that invest in gold have been standout winners. The most notable: Van Eck International Investors Gold, up 22.2% a year, and Tocqueville Gold, at 21.9% a year.
Technology also has been a big gainer, with Apple driving most of the gains in the sector, according to Standard Poor's analyst. The Berkshire Focus fund has gained 19.5% a year, betting on technology stocks. The ProFunds Internet UltraSector Inverse fund has put up an 18.3% annualized return over the past four years.
But the biggest winner of them all has been the Oceanstone Fund. That no-load, fund, which only invests in U.S. growth stocks, has posted an annualized return of 47.2% and seen its assets grow from $752,500 to $26.5 million.
Oceanstone, however, is "pretty mysterious,'' said Morningstar director of mutual fund research Russ Kinnel.
It is an "obscure fund, with amazingly good numbers and the manager won't talk to anyone,'' he said.
That manager is James Wang, a reclusive former biochemist, according to Fortune. He runs the fund out of San Diego, but the firm lists its offices on a commercial street in Broadview Heights, Ohio.
He doesn't describe his methods in filings about the fund and his "intrinsic value" approach appears to boil down to find stocks that have price-earnings ratios of less than 12 and whose earnings are expected to increase 20% a year. Among his big winners: Dollar Thrifty and Avis Budget, the rental car companies. But Kiplinger nonetheless calls its operations "a riddle wrapped inside an enigma.''
The biggest losers are concentrated in funds that pick a direction, pick an industry or region to invest in and use leverage to try and amplify results.
"If you've leveraged a short position and in an investment class that goes up, that's brutal,'' said Kinnel.
To wit, ProFunds. Six of the 10 biggest losers are products of the creator of "geared funds.''
Its leveraged funds try to magnify the returns of a given benchmark by two or three times its daily return. The intent is create big returns with less cash.
Its inverse funds seek to create gains when benchmarks fall or vice versa.
The ProFunds UltraShort Latin America Services fund was the biggest loser in this period, with an annualized decline of 52.4%.
The ProFunds UltraShort Emerging Market Services fund was next at 43.1% down a year over the last four years.
Also in the bottom 10: ProFunds UltraShort Small-Cap Services (-41.8% a year), ProFunds UltraShort China Services (-41.7% a year), ProFunds UltraShort NASDAQ-100 Services (-40.4%) and ProFunds UltraShort Mid-Cap Services (-38.7%).
Any time you use leverage, "you are going to have some extreme performance,'' said Kinnel.