This study examined stock price reactions to the disclosure of consolidated financial statements and then tested the correlation between the magnitude of stock price reactions and firm size. Contrary to the general firm size hypothesis, which predicts a negative correlation between the magnitude of stock price reactions and firm size, this study predicts a positive correlation between the two. Regarding consolidated financial information in Korea, there is virtually no difference in information availability across firm sizes that is typically observed, and moreover, predicting the consolidated financial information of large firms that generally belong to chaebol groups is expected to be more difficult than for small firms that are non-chaebol companies; therefore, when actual consolidated information is disclosed, the stock price reaction of large firms is predicted to be greater than that of small firms. Testing 479 consolidated entities during the 1993–1995 period using the variance of excess stock returns, significant stock price reactions were observed during the week including the consolidated financial statement filing deadline (disclosure week) and the preceding week. When the total sample was divided into large and small firm groups based on common stock market capitalization, the stock price reaction of large firms was generally greater than that of small firms, and in regression analysis, firm size showed a positive correlation with the magnitude of stock price reactions. However, when a chaebol dummy variable was added as an explanatory variable, firm size lost its significance while the chaebol dummy variable was significant. Therefore, considering that most chaebol firms are large firms, the finding that large firms exhibited greater stock price reactions compared to small firms is attributable not to differences in firm size but to chaebol affiliation. In supplementary analyses, the ratio of consolidated total assets to individual total assets and the number of subsidiaries—used as proxy variables for consolidation structure complexity—did not show significant correlations with stock price reactions, but the number of affiliated companies—a proxy variable for chaebol structure complexity—showed a significant positive correlation with stock price reactions, indicating that the characteristics of the chaebol group to which the parent company belongs, rather than the characteristics of parent-subsidiary relationships based on consolidation criteria, explain the cross-sectional differences in stock price reactions. In conclusion, although results vary depending on how variables are measured, a reverse firm-size effect generally appears, and this phenomenon is attributable not to differences in firm size or consolidation structure characteristics but to the characteristics of chaebol groups.