At the end of the year 2011, there were 158 SET listed companies in the three sectors used as samples of this study: 41, 39, and 78 companies in Agro & Food Industry, Consumer Products,and Industrials, respectively. Non-manufacturing companies, those did not remain listed throughout the period studied, and one company in Industrials industry that was deemed to be
an outlier of the data set were excluded, leaving 104 companies in the final sample. Table 1 shows the number of
sample companies in each of the three industries.