To help understand mergers and acquisitions (M&As), this paper utilizes the most recent M&A data (1991-2007) to establish empirical facts on a variety of performance measures for M&A acquirers, targets, and non-participants. Unlike the finance literature which mainly focuses on abnormal returns, our performance measures include firm size, technology, productivity, and profitability. Generally, in domestic M&As, in cross-border M&As, in the pre-merger period and in the post-merger period, acquirers perform better than targets, whereas targets perform better than non-participants. Firms' performance is improved after the M&As. We also find that in the pre-merger period, US firms that acquire foreign firms in developing countries are significantly better than those that acquire foreign firms in developed countries.