In applying the earnings test set forth in section 556 of this title to any such institution, whether or not in legal existence during the whole of such five years next preceding the date of investment by the insurer, which has at any time during the five-year period acquired substantially all of the assets of any other institution or institutions by purchase, merger, consolidation or otherwise, or has been reorganized pursuant to bankruptcy law, the earnings of the predecessor or constituent institutions, or of the institution so reorganized, available for interest and dividends for such portion of the five-year period as may have preceded such acquisition, or such reorganization, may be included in the earnings of such issuing, assuming or guaranteeing institution for such portion of such period as may be determined in accordance with adjusted or pro forma consolidated earnings statements covering such portion of such period and giving effect to all stock or shares outstanding, and all fixed charges existing, immediately after such acquisition, or such reorganization.