  In this paper we extend the concept of Competitivity Graph to compare series
of rankings with ties ({\em partial rankings}). We extend the usual method used
to compute Kendall's coefficient for two partial rankings to the concept of
evolutive Kendall's coefficient for a series of partial rankings. The
theoretical framework consists of a four-layer multiplex network. Regarding the
treatment of ties, our approach allows to define a tie between two values when
they are close {\em enough}, depending on a threshold. We show an application
using data from the Spanish Stock Market; we analyse the series of rankings
defined by $25$ companies that have contributed to the IBEX-35 return and
volatility values over the period 2003 to 2013.
