This article revisits the late seventeenth-century histories of two of England's most successful overseas trading monopolies, the East India and Royal African Companies. It offers the first full account of the various enforcement powers and strategies that both companies developed and stresses their unity of purpose in the seventeenth century. It assesses the complex effects that the ?Glorious Revolution? had on these powers and strategies, unearthing much new material about the case law for monopoly enforcement in this critical period and revising existing accounts that continue to assert the Revolution's exclusively deregulating effects and that miss crucial subtleties in the case law and related alterations in company behaviour. It asks why the two companies parted company as legal and political entities and offers an explanation that connects the fortunes of both monopoly companies to their public profile and differing constituencies in the English empire and the varying non-European political contexts in which they operated.