This article examines the historically contentious relationship between the financial market and the public as discussed in academic literature, financial journalism and prescriptive how-to invest handbooks during the late 19th and early 20th centuries. Although financial markets thrive off active public participation, speculating at stock and commodity exchanges has been a sanctioned ritual reserved for a privileged minority. We argue that the financial establishment’s intent to control market access through financial entry-barriers (such as exchange membership fees and margin requirements) has (...) been part of a bigger story we need to understand: a history of delegitimating uninitiated ‘lay speculators’ through the construction of exclusionary narratives about unfit amateur investors and morally corrupt publics. We conceptualize this process as an ongoing and delicate boundary-making exercise contributing to a market participation discourse that has been characterized by a set of reductive binaries, such as those of insider–outsider, professional–amateur and speculator–gambler. We show, however, that attempts to delineate popular participation in financial markets through these binaries have been complicated by the idea that besides being a force of market instability and collective irrationality, the public was a largely untapped source of liquidity. We argue that today’s discourse on public participation in financial markets resuscitates these simplified narratives and propose a more nuanced view of non-professional market participants being both destabilizers and liquidity-providers. (shrink)