Wall Street analysts cut their ratings and estimates for stock exchange companies Monday, saying they face increasing threats to their businesses from declining trading volumes and the sinking value of international currencies.

Shares of NYSE Euronext (NYX) took the hardest hit from the analyst comments, declining 9.5% to $19.90 in morning trading. Analysts at Goldman Sachs and Keefe, Bruyette & Woods downgraded their ratings of NYSE, saying it faces problems beyond lower volumes due to its heavy exposure to European markets.

Citigroup analyst Donald Fandetti cut earnings estimates for all the exchange operators Monday. "The slower volumes reflect a world where hedge funds have deleveraged, Wall Street has consolidated and risk taking has been dialed back," he said in a research note.

Goldman Sachs cut its rating on NYSE to sell and cut its price target to $19 from $33, saying that in addition to the lower trading volumes hurting exchanges in general, NYSE has the most direct exposure to the falling value of the euro and the British pound, as it generates 48% of its revenue from Europe.

Goldman also cut Nasdaq to neutral based on its exposure to European trading, though the firm said Nasdaq is less exposed than NYSE, with about 28% of its revenue coming from Europe.

The value of the euro versus the U.S. dollar has fallen 13.5% in the last year, while the pound has fallen 26%.

Goldman also said NYSE's decision to offer higher fee rates to specialists to increase its market share will hurt its earnings in the near-term, by about 15 cents per share in annual earnings.

KBW cut its rating on NYSE to market perform and its price target to $25 from $38, and also cited the effect of unfavorable exchange rates as well as more significant pressure on U.S. and European cash equities and weaker trading volume at the start of the year than it had expected.

-By Ed Welsch, Dow Jones Newswires; 201-938-5244; edward.welsch@dowjones.com

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