From the Greek megas, meaning great, this expression refers to a business deal that entails a great deal of money. Mergers and acquisitions that involve substantial amounts of money are examples of mega deals that occur with frequency in the business world. Although much merger activity happens on an ongoing basis, mega deals involve well known, established companies.

Oracle's acquisition of Sun Microsystems in a deal valued at more that $7 billion is an example of a mega deal. Such deals usually create a dominant player in the industry, or are intended to create a well-situated conglomerate.