NEW YORK ( TheStreet) -- Shareholders of American funds should be delighted with the performance of American Funds Growth Fund of America ( GFFFX). This year the fund returned 22%, topping the S&P 500 by 4 percentage points and surpassing 93% of large growth peers, according to Morningstar.The strong showing should not come as a surprise. During the past 15 years, the fund crushed the benchmarks, returning 8.2% annually and topping the S&P 500 by more than 3 percentage points. But not everyone is impressed. During the past year, shareholders withdrew $34 billion in assets from the fund, a huge outflow from a portfolio that has $112 billion. Growth Fund of America is not the only American funds portfolio that delivered winning returns and suffered outflows. American Funds Fundamental Investors ( FINFX) returned 18.6% this year, but it recorded outflows of $2.8 billion. American Funds Capital World ( WGIFX) suffered $8.2 billion in outflows, even though the fund returned 19.8%. Why are so many shareholders throwing in the towel? Many appear to be caught in a panic. Shaken by the financial crisis, investors have been dumping large-cap equity funds and shifting to bonds. But so far the exodus has been a mistake. During the past three years, equity funds have outdone bonds by a wide margin. Now the outlook is positive for 2013. With housing markets improving, the economy should grow. Chances are that the fiscal cliff will be resolved, giving consumers more confidence to spend. The outflows have been particularly severe for actively managed funds, which aim to outdo the benchmarks. Angry that portfolio managers provided little protection in 2008, shareholders have been selling active funds and buying ETFs and index funds. Plenty of fund companies have suffered outflows. But the exodus is particularly noticeable at American Funds, overseeing $915 billion in assets, American accounts for 10% of all mutual fund assets and ranks as the largest company that focuses primarily on actively managed equity funds. American Funds grew over decades by following a conservative brand of stock picking. While other companies launched faddish funds, American focused on disciplined strategies that sought to buy undervalued blue chips. The funds were sold by legions of financial advisors who trusted the company to deliver returns that would satisfy clients.