The number of SIM cards in Poland decreased by 1.494 million in the fourth quarter of 2016, according to the data published by the Central Statistical Office. At the end of December, telecom operators had 54.74m SIM cards in their bases, as compared to 56.23m at the end of September and 57.17m at the end of June. This means that over the six months, the market shrunk by 2.5 million SIM cards. The losses are observed mainly in the pre-paid segment, affected by the anti-terrorism law introduced in July. According to the act, pre-paid cards must be registered by 1 February 2017 or they will be deactivated.