Total number of GSM subscribers which had peaked at almost 150 million in November last year, dropped to 148.6 million by end of the year.
However, on a year-on-year basis the industry subscriber base rose by about 8.9 per cent from 136.6 million in December 2014 to 148.6 million in December 2015, while MTN still dominated market share.
A report from the Nigerian Communications Commission (NCC), indicated that the decline in the fourth quarter of the year which represented a reversal of third quarter growth was due to declines in MTN subscriber base from 62.4 million to 61.2 million and Etisalat from 23.4 million to 22.1 million.
Globacom and Airtel witnessed increases in their number of subscribers.
The total number of subscribers has increased rapidly over the previous decade, but in recent years of the second decade in the life of the industry in Nigeria a lower growth rate have been recorded, possibly as market penetration is already high, which leaves less room for large expansion.
The report also indicated that 2015 was a more active year for porting activities than 2014, as total incoming porting increased by 42.88 per cent to 212,401 from 148,652.
This was driven to a large extent by Etisalat, who gained 137,466 incoming porters in 2015 compared to 69,364 in 2014, an increase of 98.18 per cent.
On the other hand outgoing porting activity increased by 50.38 per cent to 219,559 from 145,998 between 2014 and 2015.
This increase was driven mainly by MTN which lost 125,515 porters in 2015 compared to 67,039 in 2014, an increase of 87.23 per cent.
Airtel also lost substantially more porters in 2015 at a total 41,527 compared to 25,883 in 2014, an increase of 60.44 per cent.
Porting activities refer to the transfer of subscribers to different network carriers, where incoming porting activities refer to those subscribers that have joined a network, whilst outgoing porting activities refer to those who left a network carrier.
The report also indicated that GSM internet subscriptions followed similar trend as telephony, except that a real drop below previous quarter was recorded. Internet subscription as at end of fourth quarter was 97.03 million as against 97.06 million in the third quarter.