The economic crisis and the influence that construction activity has on the world economy and, particularly, on the Spanish economy, make it interesting to focus this paper on both construction and real estate firms. Construction activity is responsible for an important part of the economic growth in the last decade in Spain, Europe and America. Most of the American downturns since World War II were preceded by substantial problems in housing (Leamer, 2007). In Spain, according to Seopan (2008) between 1996 and 2007 the gross added value associated with the construction industry grew at an average rate of more than 5%, although 2007 was the last year of a very long phase of expansion. Even during 2007, the gross added value, directly and indirectly associated with this sector, was 18.6% of GDP (Gross Domestic Product). Furthermore, 20% of employment was attributed to this industry. Ayuso and Restoy (2007) highlight the important role played by the housing market during recent years, as it was an indicator of the general prospects of many industrialised economies. Consequently, we study construction and real estate firms in Spain during a period characterised by economic downturns and upswings. Thus, our time period allows us to cover the last year of a crisis (1996), an upswing period that includes a bubble, and the beginning of the current crisis (2007).