The National Bureau of Statistics (NBS) yesterday said Nigeria’s Headline Inflation declined to 15.15 percent in December last year.

Although the figure is higher than 14.45per cent reported in November, the adjustment in the Consumer Price Index (CPI) increased the figure to 17.33 per cent.

The NBS in its monthly report said the December 2025 year-on-year Headline inflation rate, including all other sub-indexes, were obtained through maximisation of the index reference period, that is, using a 12-month index reference period where the average CPI for the 12 months of 2024 is equated to 100.

According to the report, “This is a departure from the single month index reference period, in which December 2024 was set to 100, which would have produced an artificial spike in the December 2025 year-on-year inflation rate. This artificial spike is induced by the base effect, which is methodological, not structural, resulting in a rate that is not in tandem with current inflationary realities; hence the need to resort to the 12-month index reference period, by equating the entire 2024 to 100.”

It noted that this definitely affects the raising factor used for the re-referencing of the 2024 CPI series and the already released year-on-year inflation rates for January to November 2025.

“This process is in line with International Best Practice as contained in the Consumer Price Index International Monetary Fund (IMF) Manual, specifically in Section 9.125 and the ECOWAS Harmonised CPI Manual, which address index reference period maximisation, following a rebasing exercise.”

It went on to state that the 2024 re-reference CPI and the revised year-on-year inflation rates for January to November 2025 can be found in the Excel Tables published together with this report on the NBS wwebsite.

The report further disclosed that the Consumer Price Index (CPI) rose to 131.2 in December 2025, up by 0.7 points from the previous Month (130.5).

“The December 2025 year-on-year Headline inflation rate stood at relative to the November 2025 headline inflation rate (17.33per cent)”

It said on a year-on-year basis, the December Headline inflation rate was 19.65per cent lower than the rate recorded in December 2024 (34.80per cent) and shows that the Headline inflation rate (year-on-year basis) decreased in December 2025 compared to the same month in the preceding year (i.e., December 2024), though with a Different base year, November 2009 = 100.

On a month-on-month basis, it said the Headline inflation rate in December 2025 was 0.54per cent, which is 0.69per cent less than the rate recorded in November 2025 (1.22per cent).

“This means that in December 2025, the rate of increase in the average price level was lower than in November 2025.