The vulnerability of small firms to price shocks may partly explain why fossil fuel subsidy removals in developing countries are so difficult to implement. This paper analyzes the effects of fuel and electricity price increases on profits of micro- and small-sized enterprises in Mexico. Using representative cross-sectional data, simulations of profit losses hint at potentially large short-term effects. First-order profit losses of a 1 per cent price increase are 0.2 per cent for fuels and 0.07 per cent for electricity, but are higher than 1 per cent for fuels in the transport sector. These effects are larger for formal than for informal firms, with energy-using low-profit firms being most vulnerable. Second-order impacts – predicted using estimated input-demand elasticities – indicate that firms react to price shocks by substituting labor for energy, while the self-employed appear to increase their own labor input. Reduced-form regressions show that some firms pass on higher fuel costs to customers.

Firm-level data spanning from 1994 to 2012 is used to investigate the apparent stagnation of Mexican microenterprises. The existence and nature of constraints are studied by estimating the empirical probability of a business’s success. A performance index is defined based on firm levels of capital stock and monthly profits. The predicted values are used to classify all microenterprises into one of three categories: upper, middle, or lower segment. Overall, the study identifies evidence of constrained productivity and capital misallocation, as well as the plausibility of cost-effective interventions. Specifically, microenterprises from the middle segment face substantial external constraints and their total share increased from 16 to 22 percent over time. The monthly marginal returns average 30 percent across lower-segment firms and 1 percent across those in the upper segment. Finally, the differences in monthly profits among segments are explored using the Oaxaca-Blinder decomposition method.