What's on the economic calendar
It's more about flows than fundamentals on the first trading day of the year.
The economic calendar is light with the Canadian manufacturing PMI from Markit at 1430 GMT and the US report 14 minutes later. Neither is likely to be a big market mover, but if either one is; it will be the Canadian one. At the moment, the market is trying to figure out what the BOC will do this month.
One thing to watch for is the reversal of the (very) late drop in the S&P 500 into the close last week.