An investigation was conducted to study a sample of 23 Greek firms listed on the Athens Stock Exchange that underwent mergers from 2011 to 2015, which is a period that embodies the Greek economic crisis. For the investigation, the authors use statistical tests to explore relative changes at twenty accounting ratios of the sample firms. These ratios are computed for one year before and after the merger. These ratios are found to be statistically insignificant indicating firms do not experience a post-merger improvement in accounting performance. The authors also examine six qualitative variables representing merger characteristics as past managerial decisions. Important findings for these characteristics include the following. First, for companies that do not fall under the same production line, the researchers observe an improvement for three ratios: collection period ratio, return on total assets, and profit or loss before tax. Thus, liquidity and profitability are improved. Second, when companies merged with their subsidiaries, the authors discover significant improvement for two ratios: gross margin and collection period ratio. In brief, positive results are found for mergers with subsidiaries and negative results with others. Third, the payment method influences two ratios, the current ratio and the stock turnover ratio. The current ratio is affected positively for the transactions in cash and negatively for the transactions in shares, while the stock turnover ratio is affected negatively for cash transactions and positively for share transactions.