Russell Fradin came with his own set of deal advisers when Hewitt Associates Inc. brought him in as CEO from Bisys Group Inc. four years ago. Fradin had moved to Bisys from Automatic Data Processing Inc., which he joined from McKinsey & Co. in 2003 and where he met Ed ­Wehle of Citigroup Global Markets Inc. Wehle, Michael Tedesco, Gautam Chawla and Tom Solomon provided Hewitt with banking advice on its $4.9 billion cash and stock agreement to sell to Aon Corp., announced July 12.

During his ADP stint, Fradin also met in-house lawyer Steven Kyono, whom Fradin hired as general counsel at Bisys and at Hewitt. Kyono began his career at Debevoise & Plimpton LLP and for legal advice on the Aon deal turned to a Debevoise team led by Andrew Sommer and Jeffrey Rosen. For antitrust advice Hewitt is using Aidan Synnott of Paul, Weiss, Rifkind, Wharton & Garrison LLP.

Aon for legal advice tapped longtime counsel Sidley Austin LLP, whose relationship with the Chicago insurance company dates to the 1980s. R. Eden Martin, who chaired the law firm's management committee from 1989 to 1999, has sat on the company's board since 2002. His successor at Sidley, Thomas Cole, led a team of lawyers on the deal that included Frederick Lowinger, Gary Gerstman, Seth Katz, Suresh Advani and Robert Lewis. Sidley also advised Aon on its $1.75 billion purchase of reinsurer Benfield Group Ltd., the $2.4 billion sale of Combined Insurance Co. of America to Ace Ltd. in 2008 and the $710 million sale of its warranty business to Onex Corp. in 2007.

On the banking side, Aon is using Bob Murley, Steve Koch, Jeff Douthit, Todd Noffke and Abzal Ayubeally of Credit Suisse Group, which also advised Aon on the Benfield and Combined Insurance deals.