The BIE does not finance the Expos. Its job is to regulate the Expos and to advise and guide the Expo organisers, participants, and the candidates of future Expos in order to ensure the success of these large-scale events.

The International Exhibitions are financed in large part by the host government. Sponsors have begun to participate in the funding of the Exhibitions.

The cost of an Expo must always be evaluated in the framework of the short and long term.

The cost can be a restraint to the organisation of an International World Expo for certain some countries but the category of the International Exhibitions that are more specialised (the Recognised Exhibitions) is a veritable opportunity for all.

The average cost of participation cannot be calculated in a general manner. Each country decides to invest in accordance with its own means.

Some decide to construct the pavilions (Registered International Exhibitions), while others having different means choose the solution of module rental.

The cost of Exhibitions is not an obstacle to its participation, since organisers often propose aid and special arrangements, notably to developing countries.

The evaluation of the financial benefits of an International Exhibition is done in the short term by the assessment of participation by states and visitors and in the long term by the evaluation of the economic impacts, often associated with the boosted tourism or with the decision of corporations to set up business in a region that is newly globally-recognised following an Expo.

The financial and commercial elements of an Expo were among the most important in the past. It is for this reason that we have the facts of, for example, the 1851 Great Exhibition in London. It cost £336,000, but received £522,000 in revenue. With time it has become more and more difficult to keep such accounts, even if normally the revenue from the Expo covers the operational costs. Indeed the Expo also demands complex financing from state funds, local authorities and the private sector. These funds are not often directly linked with the construction of the future site of the Expo, but with the infrastructure of the city or region. It is estimated that the final budget of the 2010 Shanghai Expo was larger than that of the 2008 Olympic Games in Beijing, but there has been no talk of making a loss because the positive effect for the infrastructure of the city, the quality of life and the land value of the site was vast and impossible to calculate.

Finally, the revenue of an Expo is not always expressed in a monetary value. We could probably consider the 1889 World Expo in Paris as the most successful financially; on top of the 7.5m francs that were earned at the time, we can add all the money that has been spent by tourists who have visited the Eiffel Tower until the present day.