For conducting stock repurchases, firms are supposed to choose one of the repurchasing methods between direct open market stock repurchase and indirect stock repurchase through trust contracts with financial institutions. The regulation governing direct stock repurchases requires firms to complete the repurchases within three months from the date of announcement, but the rule on indirect repurchases allows financial institutions (or firms) to repurchase as well as reissue stocks anytime within two years. In particular, the firms choosing indirect repurchases have no obligation to complete repurchases within the contract period. They may reissue the repurchased stocks also. These differences in regulation on repurchasing methods have significant implications on the value of firms. From those differences, we can hypothesize that those firms which are more financially flexible are more likely to choose direct open market stock repurchases than indirect stock repurchases. Without financial flexibility, firms cannot commit themselves to complete the repurchases within three months. We can also make the hypothesis that the fraction of shares repurchased in the indirect stock repurchases is lower than that in the direct stock repurchases. That is, the firms which choose the indirect stock repurchases are more likely to repurchase the shares opportunistically. Previous studies on this topic have simply analyzed the shareholder wealth effects of two different methods. Extending the previous analyses, this study examines the determinants of decision making on repurchasing methods, and also tests the hypothesis of opportunistic behavior which may occur in the process of firms’ decision making on the targeted fraction of shares to be repurchased and actual fraction of shares repurchased. This study investigates 877 stock repurchase disclosures from January 2000 to December 2006 in the Korean security market. The total sample consists of 404 direct stock repurchases (open market stock repurchases) and 323 indirect stock repurchases through trust contracts. We find the following results. First, the firms which choose the direct stock repurchases have significantly higher financial flexibility than the firms which use the indirect stock repurchases. Those firms using open market repurchases have higher cash flow and profitability ratios, and lower debt and growth ratios than those firms choosing indirect stock repurchases. Second, those firms choosing indirect repurchases repurchase the shares more opportunistically than those firms using direct repurchases. The actual fraction of the number of shares repurchased over the number of shares announced in the direct repurchases is more than 96%. However, it is 72.98% (in the stock market) and 67.34% (in the KOSDAQ market) in the indirect stock repurchases. Finally, that the firms choosing the indirect stock repurchases may repurchase the shares more opportunistically is reflected in the stock prices of these firms. To evaluate how the information about opportunistic behaviors are revealed in the stock prices, we regress the announcement period Average Cumulative Abnormal Returns (CARs) on proxies for theories of stock repurchases and control variables. When the targeted fraction of shares to be repurchased is included in the regression models, the dummy variable of repurchasing method is significant. However, when the actual fraction of the number of shares repurchased is included in the regression, the method dummy is not significant. The results suggest that when firms announce the targeted fraction of shares to be repurchased in the cases of indirect repurchases, investors can interpret that the targeted fractions may convey a false signal and the repurchasing method has a significant effect on stock prices. In contrast, investors regard the actual fractions of shares repurchased as reliable signals. Therefore, when the actual fraction of shares repurchased is included in regression model, the dummy variable of repurchasing method is not significant.