Between arbitrage and speculation: an economy of belief and doubt

The recent debate concerning the 'sociology of arbitrage' has firmly established arbitrage as a category of theoretical significance in the social studies of finance. In this article, I seek to complicate this debate by drawing attention to a particular kind of ambiguity inherent in the category of arbitrage, as it is put to use in financial markets. I present certain Japanese arbitrageurs' reflections on the difference between arbitrage and speculation and examine the interplay of belief and doubt underlying arbitrage operations. I argue that the resulting ambivalence towards the category of arbitrage is a marker of arbitrageurs' particular epistemological stance, identity and ethical commitment. Finally, I consider the implications of arbitrage's ambiguity for the dominant trope of speculation in the critical study of financial markets more broadly.