  We investigate weekly record sales of the world's most popular 30 artists
(2003-2013). Time series of sales have non-trivial kind of memory
(anticorrelations, strong seasonality and constant autocorrelation decay within
120 weeks). Amount of artists record sales are usually the highest in the first
week after premiere of their brand new records and then decrease to fluctuate
around zero till next album release. We model such a behavior by discrete
mean-reverting geometric jump diffusion (MRGJD) and Markov regime switching
mechanism (MRS) between the base and the promotion regimes. We can built up the
evidence through such a toy model that quantifies linear and nonlinear
dynamical components (with stationary and nonstationary parameters set), and
measure local divergence of the system with collective behavior phenomena. We
find special kind of disagreement between model and data for Christmas time due
to unusual shopping behavior. Analogies to earthquakes, product life-cycles,
and energy markets will also be discussed.
