My colleague who made the previous post had neglected to look at the cause of the so-called spike in inactive SIMs. The cause is a change in definition, plain and simple. The market revaluation has been triggered by rule changes in the activity period allowed for prepaid users and the effect of mandatory SIM registration. Previously, users would see their services terminated if they had not recharged their prepaid cards or placed/received a call within a period of 180 days. In 2010, that period was reduced to 90 days and, recently, the TRAI has reportedly reduced the period to just 20 days.