Before banks rose to dominate credit markets, ordinary people raised credit themselves or through alternative intermediaries. However, obtaining a comprehensive overview of the size and functioning of the non-bank segments within the credit market has been a great challenge for historians. Notarial deeds are widely available, but typically shed light on the borrowing of relatively well-to-do members of society. Probate inventories and insolvency records do provide insight into the modest loans of ordinary people, but only haphazardly and not for the overall stock of loans. This article exploits an exogenous shock, the Discipline Act introduced in the Netherlands in 1856, which forced lenders to record all unredeemed loans they had provided to a particular group of borrowers: seafarers. The c.14,000 loans that were recorded, in combination with several additional sources, provide a unique insight into the overall size, composition and functioning of a particular segment of the non-bank credit market.