In this paper we analyse a specific legal clause inserted in debt contracts in the late Medieval Low Countries: the ‘leistinge’ custom. It implied personal sureties, i.e., vassals or councillors of the debtor (and sometimes himself) who had to go sojourning in an inn for an unspecified period, and there live, eat and drink conspicuously (“as good pledges should do”). This legal mechanism often implied high aristocratic debtors with, in a first stage, ecclesial creditors (as abbeys) and Italian financiers. We show how the innkeeper played an instrumental role in this framework. In Brussels, the technique fostered undoubtedly the use of alternative currencies by noble pledges to circumvent the lack of cash money or the intricacy of exchange rates. Later, this credit technique also spread among local merchants and well-off burghers as debtors and creditors, especially in Northern Low Countries as exemplified by our example of Kampen. In the latter city, this legal tool could well have been favoured by town authorities as an indirect regulation of the property market, avoiding therefore too much speculation on the urban plots during periods of expansion and works of public concern. The efficiency of this custom remains somewhat open to debate, the long-time span of its use suggesting a relative efficacy, whereas its sudden suppression (as in Kampen) hints at some abuses.