As anyone who has opened their brokerage statement lately knows, the stock market hasn't come close to making up all of the ground it lost in the latest downturn. The broad market is still down about 25% from its 2007 peak. Mutual funds, where millions of Americans store their retirement wealth, have suffered right along with the rest of the market.

But not all funds were down for the count. A recent Wall Street Journal article highlighted that although the vast majority of funds lost money for all of 2008 and 2009, 45 funds posted positive inflation-adjusted returns for this period. No doubt these funds will attract a lot of attention from return-starved investors. But does that mean you should buy them, too?

The elite few
According to the Journal, of the 45 winners, six funds posted double-digit returns over 2008 and 2009. The investment that landed at the top of the heap was socially responsible fund Appleseed (APPLX). The fund posted an impressive 14.5% gain over those two years, thanks to the performance from holdings like SPDR Gold Trust (NYSE:GLD) and call-center operator ICT Group (NASDAQ:ICTG)

However, investors should note that this is a very concentrated offering, with a mere 25 positions. That means wide swings in performance are likely. Management's stock calls worked out very well in recent years, but if one or two names blew up, they could drag the fund down. Also, the fund has only been around for three years. While Appleseed certainly looks promising, I'd like to see a few more years of extended performance before making a call on its long-term prospects.

Intrepid Small-Cap (ICMAX) pulls in with a 14% return over those two years, fueled by strong industrial performers like Pan American Silver (NASDAQ:PAAS). Management's stock calls have been good here, but a closer look also reveals historically high levels of cash, averaging about 18% over the past three years. Such a stance likely protected the fund from the worst of 2008's downturn, which translated to less ground to make up in 2009. Intrepid Small-Cap is a little more than four years old, so again, I'd like to see some more extended performance. The fund looks like it could be a long-term winner, although with a 1.52% expense ratio, it's a bit pricey for the average investor.

Also making its way onto the top list was Yacktman Focused (YAFFX). This large-cap fund invests in names like Microsoft (NASDAQ:MSFT), Coca-Cola (NYSE:KO), and Pfizer (NYSE:PFE), and it landed an 11.6% annualized return over 2008 and 2009. Like the Intrepid fund, Yacktman Focused tends to keep a higher-than-average amount of cash, averaging 12% in the past three years, which likely helped on the downside. Historically, the fund has done extremely well in bear markets, but it tends to lag in more bullish times. As the name suggests, sector allocations tend to be concentrated here, so performance can be lumpy. This fund is a bit quirky, but I don't think it's a bad choice at all for patient investors.

A singular focus
The last three funds that racked up a double-digit return in the past two years were USAA Precious Metals and Mining (USAGX), Burnham Financial Industries (BURFX), and Tocqueville Gold (TGLDX). You can probably guess why they've done so well recently -- they invest in areas that were among the top performers in 2009. I'm not a fan of single-sector funds by any means, and I don't think most investors need such funds. They are typically very volatile and risky, and many folks pile into these types of funds only after they see hot performance, which means they are bound to be disappointed when those returns don't persist.

That being said, USAA Precious Metals and Mining is actually one of the better metals funds around. It has a long-tenured manager, a top-rated track record, and reasonable expenses. Tocqueville Gold is also a reasonable choice for investors who want dedicated gold exposure, but investors should expect a lot of volatility here, especially if the current gold rush runs out of steam. Burnham Financial Industries invests in smaller financial names such as Invesco Mortgage Capital (NYSE:IVR), which avoided the brunt of the downturn that larger financial institutions experienced. However, this fund is very pricey, with a 5% front-end load and a 1.92% net expense ratio.

So while management of these top-performing funds certainly deserves credit for posting positive returns in an extremely difficult environment, that doesn't necessarily mean that you should run out and buy them. When considering recent performance, it's always smart to look beyond the numbers and do some research to see whether a fund is really right for your portfolio.

For more insider investing and personal financial planning tips, check out the Fool's Rule Your Retirement service, which provides top-notch retirement and mutual fund advice. You can start your free 30-day trial today.

Amanda Kish is the Fool's resident fund advisor for the Rule Your Retirement investment newsletter. At the time of publication, she did not own any of the funds or companies mentioned herein. Coca-Cola, Microsoft, and Pfizer are Motley Fool Inside Value picks. Coca-Cola is a Motley Fool Income Investor selection. Motley Fool Options has recommended a diagonal call strategy on Microsoft. The Fool has a disclosure policy.