Plebeian finance represents a new approach to the regulation of the financial sector. Forty years of inequality have seen democratic theorists such as John McCormack and Jeffrey Green argue that we need to revive the democratic models of Ancient Rome. Its plebeian class had second class status: plebeians were able to vote, but their votes counted for less than those of the Senatorial and Equestrian classes. Yet the plebeians had distinctive democratic institutions with which they oversaw the elite classes of the republic via a public veto, regulation by publicity, and by placing disproportionate burdens on their elites. What would be the upshot of applying this radical democratic model to finance? If we understand finance as the dispensing of the sovereign public's full faith and credit, this new approach gives a novel underpinning to the separation of investment from other banking, a financial transactions tax, and regulation by exposure to public scrutiny. An inter-disciplinary combination of approaches from economics, law, political economy and political philosophy, the project of plebeian finance dispenses with the standard picture of the sector as made up of private agents whose activities would be disrupted by "red tape" - to the point where regulation might see the supply of credit "dry up". Most money creation is private and multiplicative: the micro-informational perspective of banks leverages the macro-informational perspective of a nation-state's central bank. The privilege of dispensing the "full faith and credit" of the sovereign public can reasonably be accompanied by democratic regulation given that it is constitutive of the operations of the financial sector that it is granted permission to "create" money privately. This project extends novel approaches in democratic theory to a field where regulation is politically contested and in constant danger of being rolled back to "light touch" regulation.