## 4 Results  
Table 1 displays the descriptive statistics for variables analyzed in the context of sticky costs. The change in operating costs (\(\Delta InOC_{t}\)) across the entire sample (Panel A, Table 1) averages 0.033 with a median of 0.019, indicating a modest upward trend. The standard deviation, at 0.126, suggests moderate variability in operating cost changes. Similarly, the change in sales (\(\Delta InSALE_{it}\)) has an average of 0.032 and a median of 0.016, also reflecting a slight upward movement with a larger standard deviation of 0.143, indicating more significant dispersion in sales changes compared to operating costs. The leverage ratio, measured as the ratio of total debt to total assets (\(DEBT_{it}\)), shows an average of 0.350 and a median of 0.337, with a standard deviation of 0.180, pointing to relatively low variability across the sample. The variable indicating a sales decrease in the previous period (\(SD_{it}\)) averages 0.538, suggesting that about 53.8% of the sample experienced a declining sales trend. Panel B of Table 1 details the variables by country. In Denmark, changes in operating costs and sales, at 0.008 and 0.004, respectively, suggest a relatively stable economic environment with low variability in both metrics. Denmark's leverage ratio, slightly higher at 0.386, and a sales decline rate of 0.444 in the previous period indicate less frequent sales declines compared to the overall sample average. Finland, with a change in operating costs of 0.004 and a more significant change in sales of 0.036, indicates that sales fluctuations exceed those in operating costs. Finland's leverage ratio at 0.375, near the whole sample's average, and a sales decline rate of 0.485 in the previous period show a marginally lower occurrence of sales declines than the general sample. Iceland reveals higher changes in both operating costs and sales (0.09 and 0.104, respectively), suggesting a more volatile economic condition. Its leverage ratio, at 0.337, closely aligns with the Nordic average, accompanied by a sales decline rate of 0.500, indicating an even distribution of sales declines in the prior period. Norway reports changes in operating costs and sales of 0.09 and 0.046, respectively, also marking the lowest leverage level among the Nordic countries at 0.313 and the highest sales decline rate at 0.684 in the prior period. This points to significant operational cost fluctuations and a high frequency of sales declines. Sweden, with minimal changes in operating costs (0.001) and sales (0.005), suggests a very stable economic situation with minimal variation in these metrics. Its leverage ratio of 0.344 and a sales decline rate of 0.519 in the previous period indicate a moderate tendency toward reduced sales. Collectively, the Nordic countries (228 observations) show changes in operating costs and sales of 0.026 and 0.029, respectively, reflecting moderate economic dynamics across the region. Their leverage ratio of 0.348 and a sales decline rate of 0.571 in the prior period offer a balanced view of sales decline trends in the Nordic area. Spain, with 581 observations, displays changes in operating costs and sales of 0.033 and 0.032, suggesting consistent variability in both metrics. Its leverage ratio of 0.351 indicates a level similar to the Nordic countries, with a sales decline rate of 0.525 in the previous period, suggesting a comparable trend in sales declines. Table 2 presents the findings of the regressions. While the prevailing body of literature on cost behavior analysis has predominantly employed Ordinary Least Squares (OLS) estimations, offering foundational insights into the dynamics of cost management within firms, our research seeks to advance this understanding by adopting a more detailed analytical framework. The application of OLS, although widely accepted for its simplicity and ease of interpretation, may not fully capture the intricate dynamics of endogeneity that characterize the relationship between operating expenses and sales revenue.