This paper analyses the privatizations in the Spanish stock market. We examine after-market prices and trading volume for public offerings of state-owned companies fron 1986 to 1997. The results show, in the first trading day: first, that public offerings are significantly underpriced, that is greater for initial than for subsequent public offerings and greater for small investors than for institutional investors; and second, a significant trading volume, that leads these stocks to be the most highly traded. Furthermore, we document a significant participation of small and international investors in the privatization process in Spain.