The Canadian dollar closed lower against the American currency Thursday as more data showing an improving economy raised doubts about whether Federal Reserve chairman Ben Bernanke will signal another round of stimulus measures.

The loonie dropped 0.28 of a cent to 100.78 cents US.

Uncertainty picked up after U.S. retailers reported strong sales gains for August. And the U.S. Commerce Department reported that consumer spending rose 0.4 per cent in July, the best showing in five months.

Those reports came on top of the release of the Fed's latest regional survey Wednesday, which showed the pace of U.S. economic growth is expanding.

Other data showed the economy grew faster than earlier reported in the April-June quarter, at a 1.7 per cent annual pace.

All in all, the reports served to raise doubts over whether Bernanke would use a speech Friday at the central bank's retreat at Jackson Hole, Wyo., to hint at further stimulus measures.

Hopes for further Fed stimulus had grown since the release of minutes from the Fed's last interest rate meeting Aug. 1, which showed a growing number of members wanting to inject another round of stimulus into a weakening economy.