Though the fourth-quarter results for Calamos Asset Management (Nasdaq: CLMS) beat analysts' estimates, it still wasn't a quarter -- or year -- to write home about.

For the quarter, Calamos posted revenue of $125 million, up 2% from the fourth quarter of 2006. Earnings per share grew a somewhat faster 11% and came in at $0.42. For the full year, revenue decreased 2% while earnings per share were down 16%. The company did have a few large expenses during the year that it considers to be one-time in nature -- netting out those, EPS declined just 6%.

As might be expected from the results, assets under management were likewise lackluster. On a sequential basis, AUM fell 1% as $59 million flowed out of funds and $479 million was lost in market depreciation. For the full year, AUM increased $1.5 billion, thanks to strong appreciation of $5.1 billion. The strong performance couldn't keep investors from yanking money, though, and the company saw net redemptions of $3.6 billion during the year.

The story of Calamos is really one of over-reliance on a successful but volatile fund. Calamos' growth fund -- a Morningstar four-star fund that has returned almost 15% annually over the past five years -- currently holds over $16 billion of the company's total $46 billion under management.

The upshot of course is that the fund has been very successful. But what are the characteristics of the typical growth investor? That's right: fickle and ready to pull money out when performance starts to lag. Though the growth fund has been a great performer over time, performance hasn't come in a straight line. For example, though it outperformed the S&P by nearly 18% in 2007, it sorely underperformed by 14% in 2006. And thus far, 2008 hasn't been particularly kind to growth stocks. Major Calamos Growth holdings like Apple (Nasdaq: AAPL), Google (Nasdaq: GOOG), and Garmin (Nasdaq: GRMN) have been clobbered in January, and the fund overall is down 13% versus the S&P's 6% drop.

Management hasn't missed the fact that it needs to diversify, but it's tough to bring funds up to a size that would start balancing out the growth fund overnight. Over the past few years, Calamos has added a fund of funds that combines three of Calamos' funds, an international growth fund, and a blue chip fund. More recently, it's added a global equity fund and a bond fund. With over $500 million under management, the international growth fund is the largest of these, and most of them are still sub-$100 million funds.

While there's certainly a compelling story here, given the proven success of Calamos' growth fund, it's hard to get too excited when competitors like T. Rowe Price (Nasdaq: TROW) and Janus (NYSE: JNS) have been delivering such great results.

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