(Adds that consumer goods are the second-best performing industry.)

BOSTON ( TheStreet) -- The most promising stocks may be those that have kept rising to new highs. That flies in the face of conventional investing wisdom, which says to buy low and sell high.

Software-services company IBM ( IBM), fast-food chain McDonald's ( MCD) and warehouse retailer Costco ( COST) are among S&P 500 Index shares that have climbed to new 52-week highs during the past week, producing gains of as much as 26% over 12 months.

But they have a feather in their cap: The companies' shares are handing investors profits without undue risks. In a year of record volatility, when investors veered between riskier and defensive stocks, the real winners were those in the middle.

In addition to IBM, McDonald's and Costco, chipmaker Intel ( INTC), payments processor MasterCard ( MA) and upscale supermarket Whole Foods ( WFMI) have been among the biggest gainers in the past six months and one year in risk-adjusted terms, which penalizes companies with high volatility.

Failing to make the cut are iPhone maker Apple ( AAPL), online auctioneer eBay ( EBAY) and Internet retailer Amazon ( AMZN), whose up-and-down swings make them too risky for conservative investors. Warren Buffett, the billionaire value investor, thinks as much. The one technology stock he owns is IBM, not Apple or even the staid Microsoft ( MSFT).

Even if volatility weren't a factor, some safer companies' shares landed at the top of the charts. Those include Cabot Oil & Gas ( COG) and VF Corp. ( VFC), a conglomerate that owns outdoor clothier The North Face, Lee jeans and Vans sneakers. VF Corp., in particular, flies beneath the radar, even though it's posted average annual returns of 18.5% in the past decade and raised its dividend every year for 39 years. In fact, the consumer-goods sector, which includes apparel makers, yielded the second-best returns overall in the S&P 500.

Consistent winners may extend their gains in the months ahead because they've already thrived despite slowing U.S. economic growth over the past five months, Europe's year-and-a-half debt crisis and weaker demand in some emerging economies in the current quarter. McDonald's, for example, said today that November sales at stores open at least 13 months jumped 7.4% across the world, propelled by Asia. Analysts had forecast a rise of 5%.

If global growth concerns drag on, widely expected by economists, analysts and investors, the credo of "buy low, sell high" may soon become "buy high, sell higher" -- but only with companies that have proven their mettle. The S&P 500 Index's wild ride this year -- it dropped 19% from May through September but is little changed since the start of January -- has driven many investors to low-yielding Treasuries and cash. That's clearly a mistake as select stocks are rising as profit margins near a peak.

Many top performers this year, in risk-adjusted terms, also pay high dividends, which add to performance and make the prospect of holding low-yielding bonds ludicrous. Companies including tobacco company Reynolds American ( RAI), electricity generator Southern Co. ( SO) and oil and gas producer Oneok ( OKE) carry dividend yields of as much as 5.42%, and eight of the 20 best-performing S&P 500 members boast yields of more than 2%, beating Treasuries.

On the following page is a ranking of the 20 top-performing S&P 500 stocks on a risk-adjusted basis over the past six months, one year, three years and five years. The ranking was produced by comparing the returns over those periods (using a Bloomberg screener). Included are six-month and five-year cumulative risk-adjusted returns. Companies with high volatility put them lower on the list.

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