Various studies have been done on wealth effects and financial performance of firms in different countries but have yielded mixed results. Data on completed deals of Cross-border Mergers and Acquisitions (CBMAs) comprising public listed firms with more than ten percent of share acquisition in five East Asian countries were analysed using event study and key financial ratios. Although the results for average abnormal returns in Indonesia and Korea were inconclusive, the results for Malaysia, Thailand and the Philippines suggest that the market had reacted positively adding value to the target firms at merger announcements. There was a significant improvement in targets’ free cash flow after CBMAs when compared to both before CBMAs and also control firms after CBMAs. The results also reveal that that these five East Asian countries have moved towards more efficient markets.