TORONTO – Holiday cheer will be swapped with a dose of fear after traders return from a holiday break this week as developments over the “fiscal cliff” negotiations keep the attention of investors, and will likely lead to erratic movements in stock markets.

The shortened trading week, and traditionally low volume levels around the Christmas holiday, will likely accentuate any market shifts related to developments in the stalled U.S. federal budget talks. Congress will reconvene on Thursday.