Insurance broker and risk services firm Aon Corp. reported that profit for the second quarter rose 69 percent to $258 million, as revenues were boosted by its $4.9 billion acquisition of Hewitt Associates last year.

Total revenue increased 48 percent to $2.8 billion from the prior year quarter largely due to a 42 percent increase in commissions and fees resulting from acquisitions, primarily Hewitt.

Revenues in the insurance brokerage and risk unit rose 8.9 percent from the second quarter last year.

Total operating expenses increased 46 percent, or $747 million, to $2.4 billion due primarily to the inclusion of operating expenses related to the merger with Hewitt.

“We delivered solid organic revenue growth in our retail brokerage business while delivering on the synergy savings related to Aon Hewitt,” said Greg Case, president and chief executive officer. “While macro conditions remain challenging globally, we are firmly on track to deliver growth in 2011, our restructuring programs are delivering cost savings and we have solid financial flexibility that will continue to drive increased shareholder value, as highlighted by the repurchase of $303 million of common stock in the quarter.”