Marsh will walk away from unprofitable business globally and is prepared to lose a further $150m (£78.2m) in revenue in the process, MMC chief executive Michael Cherkasky said this week.
Speaking at an Airmic breakfast meeting in London on Tuesday, he admitted that the loss of $830m (£434m) revenue from scrapping contingent commissions would be "hard to get back", but Marsh could not afford to keep working with unprofitable clients.
"Marsh will now focus on profit and loss management. We can't work with clients that are unprofitable.
"I agree that client relationships must be built on long-term relationships and Marsh will continue to do that. But only on a commercial basis," he added.
He said that though Marsh would lose the revenue, he hoped dropping those accounts would bring "a $350m improvement on the bottom line".
Responding to a question on Marsh's tarnished reputation, Cherkasky admitted that there was "no short-term fix" and trust needed to be rebuilt in the boardroom.
"Chief executives have read the press and say we got screwed by them, why should we work with them again. It is like a bruise. It will not heal overnight. But we are ready to start a major advertising campaign and I will go across the globe and send the message that we will be transparent and we apologise," said Cherkasky.
He said that the client restitution will be restricted to the US market. "Can we afford to pay out the settlement? Yes.
"Can we afford to pay any more? No," he said.