The announcement of Plan S in September 2018 has triggered a wide-ranging debate over how best to accelerate the shift to open access. The Plan’s ten principles represent a call for the creation of an intellectual commons, to be brought into being through collective action by funders and managed through regulated market mechanisms. As it gathers both momentum and critics, the coalition must grapple with questions of equity, efficiency and sustainability. The work of Elinor Ostrom has shown that successful management of the commons frequently relies on polycentricity and adaptive governance. The Plan S principles must therefore function as an overarching framework within which local actors retain some autonomy, and should remain open to amendment as the scholarly communication landscape evolves.