Acronym for General Price Index of Market. It measures the price variance on the wholesale, consumer, and construction market. It consists of the weighted sum of three other indexes: WPI (Wholesale Price Index) with a weight of 60%, CPI (Consumer Price Index) with a weight of 30%, and NCCI (National Construction Cost Index) with a weight of 10%. The GPI-M considers all available products on the market, including what is imported, and is calculated based on prices collected between day 21 of the previous month to the 20th of the current month.