US shoppers 'exercising caution' amid uncertainty
The week after Christmas is one of the most profitable for retailers but blizzard conditions in the US have been a major blow for shops on the east coast.
Analysts say that retailers will have to extend discounting in the hope that shoppers will come back later in January.
The US economy relies heavily on consumer spending but high unemployment and falling house prices have created uncertainty over the future.
Juliana Liu reports.