The U.S. dollar is turning around and strengthening against foreign currencies, which could bring down earnings at top Internet firms, paidContent reported.

The most bleak outlook has the dollar firming up by another 10 percent by the end of 2009, which would cut earnings by about 13 percent at Yahoo!. Although Yahoo! pulls only 30 percent of its revenues from outside the United States, it's “actually the most vulnerable to the trend, given its big asset holdings in Asia (a key component of the company's current value),” paidContent reported Monday.

About US$8.71 per share comes from international investments, and if the dollar appreciates another 10 percent, the overseas contribution to Yahoo!'s share value would be reduced by $0.87, to $7.84 per share, according to paidContent.

Meanwhile, at a company like eBay, earnings could go down by 8 percent. And although it would seem Google would suffer, as more than 50 percent of its revenue comes from abroad, it is actually the “least vulnerable to currency movements, given its heightened level of profitability,” paidContent reported.