Ryan Detrick of LPL Research sums it up:
New all-time highs the first 4 days of year for the S&P 500 Index.
2 more up days and ties 1964 for longest streak of new highs to start a year.
3 more up days to tie 1987 for longest win streak to start a year.
1964 saw solid low double digit gains and 1987 saw fantastic gains first 8 months.