bias; 3) we consider galaxy samples constructed using two properties, stellar mass and star formation rate (SFR); and 4) we select haloes using two secondary parameters, halo formation time and concentration. We use the [@Guo:2013a] SAM which is a recent galaxy formation model from the Munich group implemented in a Millennium class N-body simulation with a WMAP-7 cosmology.

[@Wechsler:2006] and [@Gao:2007] study the evolution of halo assembly bias in large $N$-body simulations using a mark-correlation statistic and the large-scale bias of the mass-halo cross-correlation, respectively. [@Hearin:2016] examine the redshift dependence of assembly bias in the context of an extension of the HOD framework that incorporates assembly bias (the so-called decorated HOD), finding that the impact of assembly bias on galaxy clustering weakens at higher redshift for samples with fixed stellar mass. We aim to comprehensively investigate the evolution of galaxy assembly bias using a physical galaxy formation model. We focus here on galaxy assembly bias as reflected in the halo occupation and galaxy clustering. To our knowledge this is the first work that explicitly examines the evolution of the occupancy variation, and as a consequence, of galaxy assembly bias. Our aim is to investigate the origin and evolution of assembly 