The definition of developing or less affluent countries to be used by IMU has been revised by the IMU Executive Committee in November 2023, based on a proposal by the CDC.

For the period 2024-2026 CDC refers to data of the World Bank which classifies:

• low-income economies as those who have a GNI per capita, calculated using the World Bank Atlas method, of USD 1,135 or less in 2022;
• lower middle–income economies are those with a GNI per capita between USD 1,136 and USD 4,465 
• upper middle–income economies are those with a GNI per capita between USD 4,466 and USD 13,845;
• high-income economies are those with a GNI per capita of USD 13,846 or more.

The data about research and development spending is extracted from https://data.worldbank.org/indicator/GB.XPD.RSDV.GD.ZS

Additionally a complementary group of countries has been added which are considered by the World Bank as developed economies, but whose GNI per capita is currently below USD 20,000, and whose research and development spending is below 1 per cent of their PIB, and which do not belong to a group of countries or a political and economic alliance such as the European Union.

As in previous terms, the following subdivision into priority groups has been established for the CDC, for various purposes:

• Priority 1 (Low income): GNI per capita below 1,136 USD.
• Priority 2 (Lower-middle income): GNI per capita in the interval from USD 1,136 to USD 4,465.
• Priority 3 (Upper-middle income-low): GNI per capita in the interval from USD 4,466 to USD 7,585.
• Priority 4 (Upper-middle income-medium): GNI per capita in the interval from USD 7,586 to USD 10,706.
• Priority 5 (Upper-middle income-high): GNI per capita in the interval from USD 10,707 to USD 13,845.
• Priority 6 (GNI per capita is between USD 13,845 and USD 20,000, but research and development spending is below 1 per cent of the country's PIB, and the country does not belong to a group of countries or a political and economic alliance such as the European Union).

At any moment, IMU member countries can ask the IMU to consider inclusion/exclusion as a developing or less affluent country. The application should be motivated and well-documented. On the basis of the evidence presented by the country, the CDC would then make a recommendation to the IMU EC for a case-by-case decision. If a country's World Bank status as a developing or less affluent country has changed between the data used to decide on the status and the time of the request, this information should be included as part of the evidence.