Interest group scholars have difficulties relating policy access to influence; some suggest that access is a proxy for influence and related in a linear fashion, others identify a threshold-model where a minimal degree of ‘insiderness’ is necessary for influence and others point to several institutional and issue-specific contextual factors mediating the access-influence relationship. We conceive of influence as the ‘price’ that results from an information exchange between policy makers and interest groups. We specify respective demand- and supply-curves depending on the information needs of policy makers and the organizational capacities of interest groups. We consider the Covid-19 crisis as an exogenous shock that immediately affected the position and slope of the demand- and supply-curves. We use the variation in these curves across three time-points (pre-Covid, immediate aftermath of Covid and the longer term post-Covid time period) to evaluate the validity of our conceptual model and the relative importance of supply- and demand-factors. Our findings indicate that the Covid-outbreak constituted a ‘demand-shock’ (policymakers ad-hoc in need of information) that increased prices (more interest group influence) at first, but that supply (more lobbying) and a normalisation of demand, created an over-supply of lobby activities and decreased the price in terms of aggregate influence.