Properly analysing corporate margins is not only important for managers and investors, since they are also catalysts for indirect investment (if the reduction in margins is translated into price increases to compensate for it), interest rates (they grow with rising inflation) and employment (it is better sustained during difficult times if margins are high). In this brief note, we analyse the past, and especially recent, evolution of corporate margins in Spain. We also study their level compared to historical averages and the main factors that explain these changes. We believe that it is worthwhile to have clear ideas on the subject because there are a wide range of indicators and conclusions in the market and among the consensus of economists, which confuses the issue.