Since 1984 several financial linkages have developed: the Chicago Mercantile Exchange link with the Singapore International Monetary Exchange, Ltd.; the Boston Stock Exchange with the Montreal Stock Exchange; the American Stock Exchange with the Toronto Stock Exchange; the Midwest Stock Exchange with the Toronto Stock Exchange; the Philadelphia Stock Exchange and the Options Clearing Corporation with the London Stock Exchange; and the American Stock Exchange with the European Options Exchange in Amsterdam. The article traces the development of existing linkages and applies economic theories of market development to domestic and international market linkages. Market linkages raise regulatory issues and these, too, are discussed in the article. International linkages help to facilitate trade and increase competition, but they also must be adequately regulated. 171 footnotes.