Just three years ago, with the financial crisis at full throttle, dealmakers at some of the biggest financial companies in the United States labored around the clock to seal major deals nobody could have thought possible months earlier. J.P. Morgan Chase & Co.'s Jamie Dimon and his senior executives worked to close the distress purchases of Bear Stearns Cos. and Washington Mutual Inc. Meanwhile, over at Bank of America Corp., then-CEO Ken Lewis and his deal team struggled to bring in Merrill Lynch & Co.

In fact, the financial crisis generally provided a period of intense advisory activity for the big banks. A senior Morgan Stanley team advised the Treasury on Fannie Mae and Freddie Mac, while American International Group Inc. sought out any number of firms, starting with J.P. Morgan, on a variety of desperate restructuring and divestiture needs. And when Citigroup Inc. sold off its brokerage operations to a joint venture run by Morgan Stanley, both firms tapped their own considerable investment banking assets.

Since then, the global U.S. banks have largely gone quiet when it comes to acquisitions; their bankers, when they're called upon, are mostly ticking off potential asset sales. BofA, for instance, has dominated big bank divestitures with some $16 billion in sales this year alone, including its $5 billion disposal of a 3.3% stake in China Construction Bank Corp. As one New York-based investment banker says, "The bank deal teams I work with are all disposition focused."

All this is partly why, in this first listing of corporate dealmakers, we decided to set aside the biggest banks. Dealmaking is often a core competency at the big banks, which they provide, in exchange for considerable fees, to their corporate clients. To execute their own deals, big banks such as J.P. Morgan usually tap senior talent in their investment banking units, meaning they do not build in-house corporate dealmaking teams on any kind of permanent basis.

When the banks do have an acquisition or a divestiture, they tend to create ad hoc units to tackle various aspects of the project, as if they'd been hired by any client to provide advice, analysis and execution.

We understand there are considerable differences between lenders with sizable investment banks, such as Citi, J.P. Morgan, BofA and Morgan Stanley, and those, such as Wells Fargo & Co. and PNC Financial Services Group Inc., that are far more focused on retail banking and the middle market. But when it comes to corporate dealmaking, differences between the banks and traditional corporations still appear to us greater than the similarities. The fact is, whether in terms of regulation, accounting or culture, the banks are a species distinct from most corporations, which explains why they are not included in traditional rankings of industrial companies. At the very least, the banks deserve a separate investigation into how they organize and structure their dealmaking. Stay tuned.