The paper investigates financial characteristics of bank mergers and acquisitions (M&A) in the U.S. banking industry, employing the data for U.S. banks when M&A activities in the industry were booming in the late 1990s. It is interesting, but not surprising, to find several new attributes that relate to M&A, given the dynamically changing environment of the U.S. banking industry in the studied period, especially in the areas of technology and deregulation. This study found that acquiring banks were, overall, larger in their size and market-to-book value ratio than other groups of banks, i.e. the acquired and nonmerging banks. Acquired banks were generally less efficient in operation, compared with independent banks, and were, to a degree larger than chance would suggest, a type of bank holding company (BHC). Furthermore, the variables, size and (operating) efficiency, showed intertemporal stability between the two sample periods.