Most funds stick to a narrow specialty, such as foreign small stocks or California municipal bonds. But a handful of funds take a different approach, holding broad collections of stocks and bonds. During the 1990s bull market, the broadly diversified funds lagged hot technology funds. But in market downturns, diversification can help to limit losses.

By staying with these funds during downturns, patient investors can gain big returns over the long run.

VISITORS TO the Beijing Olympics saw the products of a remarkable construction campaign: new highways, bridges, power plants, and airports. Seeking to develop their economy, the Chinese are racing to build modern infrastructure. China is hardly alone in its boom.

DURING THE first quarter of 2008, bond markets went haywire. With investors increasingly worried about defaults, the average high-yield corporate-bond fund lost 3.6%, according to Morningstar.

HIGH GASOLINE prices are infuriating motorists, but for investors in energy stocks, the rocketing cost of fuel has been a blessing. With profits growing, shares of oil companies have been climbing impressively.

IN A year when the Standard & Poor's 500-stock index has been dropping, the average mutual fund investor should do even worse than the benchmark, says Louis Harvey, president of Dalbar, a Boston research firm. The problem is that millions of investors have panicked.

DURING THE first six months of 2008, the Standard & Poor's 500-stock index lost 12%, and most equity mutual funds suffered double-digit declines. Long-short funds were among the few that avoided losses. These resilient choices have proven their ability to make money in up years and down.

SEEKING TO attract new investors, fund companies have brought out numerous specialized choices. The fledgling funds include Claymore S&P Global Water and T. Rowe Price Africa and Middle East. This is not the first time the industry has introduced narrowly focused funds. During the bull market in the 1990s, dozens of Internet choices appeared. In the 1950s, investors could buy the Television Electronics Fund.

IN THE RECENT market downturn, small stocks have been hit particularly hard. During the 12 months ending in March, the average small-cap fund lost 11.6%, lagging large-cap funds by more than nine percentage points. This is not surprising. In bear markets investors avoid small stocks, moving to big blue chips.

It is a troubling time for investors, with both the economy and the stock market seemingly in a relentless decline. Many investors are fleeing the turmoil, moving to super-safe United States Treasury bonds. But Treasuries provide only modest returns. For better results, consider the following rock-solid investments that are suitable for even the most conservative investors.