US stocks falter on yen

Stocks have stumbled in the final session of a tumultuous week on Wall Street as the yen rallied against the dollar and concerns about the US economy still dogged investors following Tuesday's huge drop.

The Dow Jones industrials logged their worst weekly performance in four years, though stocks rose sharply last year and until this week had gone more than 45 months without a drop of more than 2% in a single session.