The nineteenth-century growth of the London Stock Exchange and the development of the market for stocks and shares are familiar topics of study. This article provides an alternative perspective on them by decentering the London Stock Exchange and focusing instead on the activities of “outside stockbrokers” – those who operated outside the Stock Exchange and its rules. Often regarded as peripheral, these brokers were in fact instrumental in promoting investment and speculation to a mass market. The article examines their innovative methods, and seeks to explain why they were so successful, despite persistent – and sometimes justifiable – accusations of fraud. It suggests how perspectives from the history of consumer society provide fresh insights into the market for financial products. And it underlines the importance of looking outside formal markets, arguing that focusing on “fringe” markets can help us to rethink boundaries, relations, and practices in the history of capitalism.