Nigeria’s four biggest mobile operators – MTN, Vee Networks, Nitel GSM and Globacom – have teamed up to lobby the government for an extension to their tax exemption status. United as the GSM Consultative Forum, the cellcos are asking the state to relieve them of the mandatory tax on their profits for another five years to help them sustain the rapid development of the mobile sector. The tax exemption status granted to all four operators expires next year.