We provide estimates of the wealth holdings of households around the world for each year since 2000. More specifically, we are interested in the distribution within and across nations of individual net worth, defined as the marketable value of financial assets plus non-financial assets (principally housing and land) less debts. No country in the world has a single comprehensive source of information on personal wealth, and many low- and middle-income countries have little direct evidence of any kind. However, a growing number of countries – including China and India as well many high-income countries – have relevant data from a variety of different sources which we are able to exploit in order to achieve our objective.

The procedure involves three main steps, the first two of which follow the structure first set out in Davies et al. (2008, 2011). (See also Davies et al., 2017.) The first step establishes the average level of wealth for each country. The best source of data for this purpose is household balance sheet (HBS) data, which are now provided by 49 countries, although 25 of these countries cover only financial assets and debts. For an additional three countries wealth levels can be calculated from household survey data. Together these countries cover 65% of the global population and 96% of total global wealth. The results are supplemented by econometric techniques, which generate estimates of the level of wealth in countries that lack direct information for one or more years.

The second step involves constructing the pattern of wealth holdings within nations. We use direct data on the distribution of wealth for 35 countries. Inspection of data for these countries suggests a relationship between wealth distribution and income distribution, which can be exploited in order to provide a rough estimate of wealth distribution for 133 other countries, which have data on income distribution but not on wealth ownership.

It is well known that the traditional sources of wealth distribution data are unlikely to provide an accurate picture of wealth ownership in the top tail of the distribution for most countries. To overcome this deficiency, the third step makes use of the information in the Forbes world list of billionaires to adjust the wealth distribution pattern in the highest wealth ranges.

Implementing these procedures leaves 37 countries for which it is difficult to estimate either the level of household wealth or the distribution of wealth, or both. Usually the countries concerned are small (e.g. Andorra, Bermuda, Guatemala, Monaco) or semi-detached from the global economy (e.g. Cuba, Somalia, North Korea). For our estimates of the pattern of global wealth, we assign these countries the average level and distribution of the region and income class to which they belong. This is done in preference to omitting the countries altogether, which would implicitly assume that their pattern of wealth holdings matches the world average. However, checks indicate that excluding these nations from the global picture would make little difference to the results.

Table 2-1 lists the 213 countries in the world along with some summary details. Note that China and India are treated as separate regions due to the size of their populations.
The following sections describe the estimation procedures in more detail. Two other general points should be mentioned at the outset. First, we use official exchange rates throughout to convert currencies to our standard measure of value, which is US dollars at the time in question. In international comparisons of consumption or income it is common to convert currencies using purchasing power parity (PPP) exchange rates, which take account of local prices, especially for non-traded services. However, in all countries a large share of personal wealth is owned by households in the top few percentiles of the distribution, who tend to be internationally mobile

Credit Suisse Global Wealth Databook 2018 and to move their assets across borders with significant frequency. For such people, the prevailing foreign currency rate is most relevant for international comparisons. So, there is a stronger case for using official exchange rates in studies of global wealth.

The second issue concerns the appropriate unit of analysis. A case can be made for basing the analysis on households or families. However, personal assets and debts are typically owned (or owed) by named individuals, and may be retained by those individuals if they leave the family. Furthermore, even though some household assets, such as housing, provide communal benefits, in households that include members other than a single individual or married couple, it is unusual for members to have an equal say in the management of assets, or to share equally in the proceeds if the asset is sold. Membership of households can be quite fluid (for example, with respect to older children living away from home) and the pattern of household structure varies markedly across countries. For all these reasons – plus the practical consideration that the number of households is unknown in most countries – we prefer to base our analysis on individuals rather than household or family units. More specifically, since children have little formal or actual wealth ownership, we focus on wealth ownership by adults, defined to be individuals aged 20 or above.