FOLKLORE has it that foreign markets are more risky than domestic markets because of political, economic, and social instability abroad. A normative implication of this belief, sometimes mentioned in the literature, is that a firm must establish itself in the domestic market before venturing into foreign markets; otherwise, it is argued, the inherent instability associated with exports might seriously damage the firm's operations. It is shown here that such implications are at variance with the diversification principle in portfolio theory. Specifically, an individual project might be very risky, yet its incorporation with other projects may decrease the overall risk of the portfolio. The overall risk of a group of projects is affected mainly by the relationships among these projects and only slightly by the individual riskiness of each. The hypothesis advanced in this study was that exports, through market diversification, tend to stabilize the firm's sales, and the larger the spread of these exports over several markets the more stable the sales. This hypothesis was tested on data selected from a sample of about 500 firms in Denmark, the Netherlands, and Israel. Results of the test were consistent with the hypothesis: sales stability and diversification of exports are indeed positively correlated.

I have benefited from comments and criticisms of an earlier draft by Irma Adelman, Peter Balacs, Ronald Dore, Edgar Edwards, Unni Eradi, Michael Faber, Anne Gordon, Keith Griffin, Jill Rubery, Seev Hirsch, Ernest Stern, Frances Stewart, Hugh Stretton, B. R. Virmani, Gordon Winston and Howard Wriggins. To these, and to a research seminar at Queen Elizabeth House, I am very grateful. I am also grateful to the Economic Development Institute of the World Bank and its Director, Mr. Andrew Kamarck, for having provided the facilities and stimulating atmosphere for the early stages of a considerably larger paper, commissioned by Mr. Ernest Stern, of which this paper forms a part. I am grateful to Mr. Stern and the World Bank for permitting me to use the material here.