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The presidential election is less than 50 days away, and investors are re-examining their portfolios. Some sectors and stocks figure to do well if President Barack Obama is re-elected, while others should benefit if challenger Republican Mitt Romney moves into the White House.

But some caution that it may be tougher than usual to predict the outcome of this election, let alone figure out how to make money from the results. Indeed, some Wall Street pros detect more caution than in some past years among investors playing the election game.

James Bianco, who runs trading and research firm Bianco Research in Chicago, says financial markets aren't yet placing big bets on either Obama or Romney. He cites polls showing the candidates neck and neck.

Conventional wisdom holds that the stock market does well when a Republican wins. Presidents from the GOP tend to favor lower taxes and less spending, analysts say. Some go as far as to say the stock market's strength this year comes as Romney's chances of victory have improved.

But the policies of presidents don't always match their campaign planks, and post-election returns also don't always fit a clear pattern, suggesting there's just so much a president can dictate when it comes to the stock market. For example, the Dow Jones Industrial Average ($NDU) fell 7.5% in the 12 months after Ronald Reagan, a Republican, won the presidential election in 1980. But it rose 12.8% the year after he was re-elected in 1984.

The Dow soared 23.3% in the year after George H.W. Bush, also a Republican, was elected in 1988. But the average also jumped 12.6% after Democrat Bill Clinton was elected in 1992 and rose 26.5% after he was re-elected in 1996.

Overall, data from Citigroup point to better returns under Democratic presidents over the course of their terms. The market also tends to do better when a challenger wins, data show.

Focus on specific sectors

A better bet is to focus on specific sectors that might outperform if a candidate wins. Tobias Levkovich, Citigroup's chief U.S. equity strategist, says "a Romney victory may benefit several industries such as energy, health care, defense, utilities and financials."

Financial shares could rise because Romney has pledged to repeal various restrictions of the Dodd-Frank financial-regulation law, Levkovich says. Defense stocks may be helped because the industry currently faces major spending cuts, but Romney has pledged his commitment to defense spending, analysts note.

John Brynjolfsson, who runs hedge fund Armored Wolf, is a fan of technology and green-energy shares if Obama is re-elected, because he's considered more open to spending in this area, and recommends PowerShares Cleantech Portfolio (PZD) exchange-traded fund. Others favor generic-drug makers, which could profit from Obama's health plan.

An Obama victory also could help Microsoft (MSFT), says Brynjolfsson, because "Obama's leaning toward industrial policy, and centrally managing major productivity initiatives," could help the tech giant. (Microsoft owns and publishes MSN Money.)

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