Shares on Wall Street pulled back from their recent winning streak on Wednesday amid concerns about debt problems in Portugal and disappointing home sales in the United States.

The Dow Jones industrial average fell 52.68 points, or 0.48 percent, to 10,836.15, while the Standard & Poor’s 500-stock index dropped 6.45 points, or 0.55 percent, to 1,167.72. The Nasdaq composite index declined 16.48 points, or 0.68 percent, to 2,398.76.

The euro slipped to $1.3338, from $1.3488 late Tuesday. It was the lowest level for the European currency since May, and continued a slide that began in November on concerns about rising debt levels in several European nations — including Portugal, Ireland, Italy, Greece and Spain.

On Wednesday, Fitch Ratings announced it had downgraded its rating of Portugal’s long-term foreign- and local-currency debt and that the outlook on the long-term debt was negative. The move reflected the fact that the Portuguese government’s 2009 budget deficit had swelled to 9.3 percent of gross domestic product, well above the 6.5 percent the ratings agency expected, Fitch said.