"The cost of borrowing cash overnight on the last day of the year has surged despite the US Federal Reserve’s injection of billions of dollars into markets in an attempt to ease the strain, raising concerns that investors may be in for a volatile final few weeks of 2019."

                                      For now a pause, an inside day for small caps

In summary, the $SP-500 chart is strongly bullish. The only sell signals are from put- call ratios. So if long, stay long and use trailing stops.

Volatility has remained mostly bullish, $VIX remains below 16 on a closing basis and that is bullish.