Unlike Aon's provision governing the non-solicitation of clients, claims Alliant, the provision in the producers' employment agreements with Alliant does not bar a former employee from accepting, servicing or otherwise entering business relationships with former Alliant clients.

Citing evidence that Alliant had put a price tag on negotiating a settlement with Aon, Fried wrote in his preliminary injunction that Alliant had planned to pay Cusack and Arkley a combined $11.5 million for their first year's annual salary as well as a combined $9.5 million in bonuses for signing and meeting certain goals.

Two-Day Hearing

Stephens, Aon's attorney, says Fried's decision is a good example of how the judge saw the evidence during a two-day hearing in a Manhattan courtroom in November.

Alliant, for its part, said in a statement that the ban and lawsuit were "a clear attempt by Aon—an industry giant—to protect its diminishing market share by misleading customers about the Court's ruling and by using litigation to prevent talented employees from pursuing more compelling professional opportunities."

Court filings by Alliant indicate that both Arkley and Cusack, plus two other key executives, were at the end of employment contracts with Aon that expired on April 30. Aon offered Arkley a short-term contract on the condition that he renew a couple of key accounts, says Alliant.

As the clocked ticked down on those contracts in early 2011, Arkley and Cusack each met separately with a top Alliant executive, Richard Ferrucci. He had worked with members of the Aon construction unit while he headed that unit and while he was employed at Willis Inc., another large broker. Ferrucci serves as trustee of Arkley's life insurance trust and is godfather to Arkley's wife.

Aon and Alliant dispute the details and significance of what was discussed. Alliant says Ferrucci was scrupulous about meeting separately with Arkley, Cusack and other Aon managers. No confidential Aon information was discussed, says Alliant, and Ferrucci testified that, during the meetings, he never mentioned to any one Aon employee that he was speaking about jobs with their Aon colleagues, too.

Even after playing a round of golf in New York and driving back to Boston together on June 12, Cusack testified that he and Ferrucci never discussed other Aon employees or Aon clients.

Also disputed is whether Arkley was terminated by Aon or resigned.

Either way, Arkley was still working for Aon when he and Cusack met with top executives of Turner Construction in midtown Manhattan on June 8. Aon was aware of the meeting and raised no issue about it, says Alliant. The meeting was called to discuss surety credit that Aon could arrange for Hochtief, Turner's German parent company that has other operating units in the U.S. (Turner has internal insurance and surety capabilities).

Aon served both Cusack and Arkley with legal papers as they left the meeting with Turner, says Stephens.

To establish a new account, a contractor provides a broker a "broker of record," or BOR, letter. On June 9, Turner delivered a BOR letter to Aon making Aon broker for a separate surety program for Hochtief. Cusack informed Aon about it, says Alliant, but Stephens, speaking for Aon, says Cusack put the letter aside in a file.

Rescinded Broker-of-Record Letter

After learning that Cusack and Arkley were leaving Aon, Turner rescinded the BOR and instead gave the work to Alliant.

Alliant agreed to indemnify Turner against liability related to switching the BOR to Alliant. A Turner executive, in an affidavit, said Turner had not been solicited to switch companies but had decided to make the change based on the qualifications of the companies.

On June 13, Arkley and two Aon colleagues sued Aon in Los Angeles Superior Court to declare unenforceable—in effect, to nullify—the restrictive covenants in their employment agreements. The judge ruled against them, based mainly on a legal technicality.