Of all stock market measures, one stands out: The Price-to-Earnings Ratio (PE).

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One of the selling points when PE firms speak with management of a publicly-traded target is getting away from the quarterly guideposts set by investors and analysts, which is an attractive alternative for companies struggling through a turnaround or trying to undertake a major growth initiative.

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The second big feature that will dominate deal making in 2013 will be the continued popularity of sponsor-to-sponsor transactions, which is sure to reignite the controversy over whether sales of assets from one PE fund to another are good or bad for investors.

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