New data from Dealogic shows that July was the fifth straight month of growth in U.S. mergers and acquisitions activity -- and the highest total since a year ago.

But it's not quite as good as it looks. The data is skewed upward by foreign bids for American companies like Genentech (NYSE: DNA) and Anheuser-Busch (NYSE: BUD) and, according to the Associated Press, "the rise in M&A ... more likely reflects foreign companies taking advantage of the weak dollar than it does a loosening of credit."

But from an investors' perspective, the cause of the increase probably doesn't really matter. Deep value investors like Mohnish Pabrai have been struggling to post strong returns of late, in part because the private equity funds that could be relied on to buy undervalued companies a couple years ago have brought their U.S.-based activity to a hault.

But now the foreign companies and sovereign wealth funds are in the game and, from an investors' perspective, that's just as good -- whoever will buy undervalued public companies at a premium will boost returns. The low price-book, low price/earnings, contrarian investment strategies that haven't worked lately could be ready to start working again, just as they have historically.