| No. | Selection criterion | In operation | Sample size |
| 1 | Geographical restrictions | German purchasing companies (acquirer nation) | 32,923 |
| 2 | Temporal restrictions | Transactions between 28.09.1998 and 02.03.2009 | 14,544 |
| 3 | Corporate structure | Purchasing companies must be listed on the stock exchange (acquirer public status: acquirer) | 4226 |
| 4 | Sector restrictions | Purchasing companies from all sectors apart from the financial, real estate, government and public authority sectors | 3212 |
| 5 | Investment restrictions | 100% transactions (percentage of shares acquired in/after transactions) | 1605 |
| 6 | Transaction status | Concluded transactions (deal status: completed) | |
| 7 | Disclosure of the transaction price | The transaction price must have been published (deal type: disclosed value M&A) | 320 |
| 8 | Transaction price/Volume | Transaction price must amount to at least 100mn US $ | 115 |
| 9 | Existence of the purchaser/Availability of the data | Purchasing companies must have existed at least up to 2011, otherwise it is not possible to retrieve their data from Thomson ONE | 88 |
| 10 | Isolation of the event | If a purchasing company carried out more than one transaction in a year, the smaller transactions (measured by the transaction price) are excluded | 78 |