[en] Highlights: • This paper presents an empirical analysis of the impact of White Certificates. • I assess the impact of energy efficiency policies on productivity and profitability. • I find a positive and significant impact of White Certificates on firm performance. • Effects are stronger if relationally and socially proximate firms are supported. This paper presents an empirical analysis of the impact of adopting energy efficiency measures, labeled “White Certificates”, on the economic performance of companies active in the paper and glass sector in Italy. White Certificates, launched in 2005, represent the longest-lasting and effective policy tool to stimulate energy efficiency, in particular for the manufacturing industry. My analyses exploit financial statements of Italian companies available from the AIDA (Computerized Analysis of Italian Companies) database with the aim to quantify the impact of these measures on the performance of firms in the two industries. The impact of energy efficiency policies is assessed on both productivity and profitability, and the effect is broken down into direct and indirect impacts, obtained by calculating spatial lags of energy efficiency support based on geographical as well social, relational, and technological proximity matrices.