  We utilize the symmetric thermal optimal path (TOPS) method to examine the
dynamic interaction patterns between the VIX and VIX futures markets. We
document that the VIX dominates the VIX futures more in the first few years,
especially before the introduction of VIX options. We further observe that the
TOPS paths show an alternate lead-lag relationship instead of a dominance
between the VIX and VIX futures in most of the time periods. Meanwhile, we find
that the VIX futures have been increasingly more important in the price
discovery since the launch of several VIX ETPs.
