In many countries there seems to be a shortage of risk capital (i.e, equity or equity-linked capital) for entrepreneurial ventures seeking external capital.As a consequence many entrepreneurial ventures are undercapitalized with a high loan-capital burden. There is some evidence from the U.S.A. that informal investors provide an essential source of equity capital to entrepreneurial ventures. However, our knowledge about the informal risk capital markets is dominated by research from the U.SA., and there are few studies carried out in other countries. This study represents the first description of the informal risk capital market in Sweden. The aim of the study is also to compare the characteristics of informal investors in Sweden with those in the U.SA. and the U.K. Information from 52 informal investors is used for the description of the informal risk capital market in Sweden.An international comparison is made by using the results of studies by Gaston (1989) on informal investors in the U.SA., and Mason et al. (1991) on the informal risk capital market in the U.K. What about the informal risk capital market in Sweden? Traditionally, the tax system in Sweden has not stimulated private wealth accumulation, and there has been a tradition to seek formal, institutional solutions to solve the problems faced by entrepreneurial ventures. However, in recent years there has been a growing interest in the potential role of informal investors to fill the equity capital gap for entrepreneurial ventures. Today, there seems to be an informal risk capital market in Sweden, even if it is not very large. In terms of investor demographics, investment activity, portfolio characteristics, and the relationship between the informal investor and the portfolio firm, the informal investors in Sweden can be characterized in the following way: They are predominantly male, and they are financially well-off. One main characteristic is that they are very experienced entrepreneurs, and it can be assumed that the majority of the informal investors have made their fortunes through a cash-in of their businesses. The informal investors in Sweden seem to be frequent investors, and their acceptance rate is rather high. Furthermore, they seem to be rather careful in their evaluation of new investment opportunities and also invest large amounts of money in their informal investments. The informal investors seem to make their investments in established firms and in more low-tech industry sectors. Therefore, they only partly seem to play a role in filling the equity capital gap for entrepreneurial ventures. The informal investors' relationship to their portfolio firms can be characterized as active but they are not involved to any large extent in daily operations. The most common way of organizing the relationship is by way of active work on the board, and by providing consulting help when needed. What are the similarities and differences between informal investors in the U.K., the U.SA., and Sweden? This study shows that there are some similarities. For example, informal investors are predominantly male, with an entrepreneurial background, financially well-off, and they identify investment opportunities from friends and business associates. On the other hand, there seem to be some important differences. For example, informal investors in the U.K. and Sweden seem to be older than those in the U.S.A. Furthermore, informal investors in Sweden invest a higher proportion of their wealth in informal investments compared to their counterparts in the U.SA. and the U.K. In terms of investment activities, informal investors in the U.K. can be characterized as less sophisticated and ad hoc investors, and they seldom make investments with other informal investors. On the other hand, informal investors in the U.S.A. and Sweden seem to be more professional in their investment activities, i.e., they make many serious evaluations of new investment opportunities, and they put rather large emphasis on the evaluation. In terms of portfolio characteristics, informal investors in Sweden seem to take the lowest risks in their investment portfolios compared to their counterparts in the U.S.A. and the U.K. Finally, informal investors in the U.K., the U.S.A., and Sweden work differently in relationship to their portfolio firms. In the U.K. the relationship can be characterized as ''passive:'' i.e., their involvement in the portfolio firms' daily operations is usually rather low. On the contrary, the informal investors in the U.S.A. work very actively in their portfolio firms. The analysis shows that there seem to be two extreme categories of informal investors. One extreme is represented by many of the informal investors in the U.K. They can be characterized as infrequent and less sophisticated investors, who invest small amounts of money and work as rather passive investors. The other extreme is represented by informal investors in the U.S.A. They seem to be more professional and active in their informal investments. Informal investors in Sweden show some similarities with their U.S. counterparts, but they work less actively in the portfolio firms than do informal investors in the U.S.A. The differences between the characteristics of informal investors in the U.K., the U.S.A., and Sweden are, of course, attributable to differences in contextual factors such as investment climate, entrepreneurial traditions, fiscal regimes, regulatory environment, and wealth distribution. This implies that it may be difficult to copy measures to stimulate the informal risk capital market from one country to another.