sample, while the red (blue) lines correspond to the cross CF of the full sample with the 20 per cent oldest (youngest) haloes in the top row of the figure, or the 20 per cent highest (lowest) concentration haloes in the bottom row (see § \[Sec:HOD\_CF\]).

![image](Fig4a.pdf){width="33.00000%"} ![image](Fig4b.pdf){width="33.00000%"} ![image](Fig4c.pdf){width="33.00000%"} ![image](Fig4d.pdf){width="33.00000%"} ![image](Fig4e.pdf){width="33.00000%"} ![image](Fig4f.pdf){width="33.00000%"}

We find that at $z=0$, haloes with early formation times and high concentrations are more clustered than ones with late formation times and low concentrations. This is the well-studied behavior of halo assembly bias (e.g., @Gao:2005 [@Wechsler:2006; @Gao:2007]). The halo assembly bias effect, as reflected by the clustering differences, is slightly stronger for the case of halo formation time than for halo concentration and extends to smaller separations. We note that as we are measuring here halo (instead of galaxy) clustering, the scales involved are all in the so-called 2-halo regime. At higher redshift (e.g., $z=3$) there is no difference in the clustering measured for haloes at the extremes of the formation time distribution and low concentration haloes are more clustered than high concentration haloes, reversing the trend seen at the present day.

We reach the same conclusions as already inferred from Fig. \[Fig:CW\], namely that the halo 