Aon said yesterday it would buy Willis Towers Watson for nearly $30 billion in an all-stock deal that creates the world’s largest insurance broker.

Both companies have significant operations in Bermuda. However, as Aon is the second largest insurance broker in the world and Willis the third, the deal is likely to face antitrust regulatory hurdles.

The deal is thought to be the largest acquisition in the history of the insurance sector.

The combined company would be worth nearly $80 billion and adds scale in a battle with falling margins and challenges ranging from the coronavirus to climate change.

In Bermuda, both companies have reinsurance and insurance broking operations and both also provide captive management services.

Aon’s island offices are on Woodbourne Avenue and Willis’s on Pitts Bay Road.

“We know each other well and this came together pretty quickly,” Aon chief executive officer Greg Case said on a call with analysts, adding that the deal was motivated by “unmet client needs”.

First mooted a year ago, the deal creates a company that will overtake market leader Marsh & McLennan in terms of value.

Aon had scrapped plans last year to pursue a merger with Willis, a day after media reports forced it to reveal it was in the early stages of considering an all-stock offer for the Irish-domiciled company. The merger agreement came right after a 12-month restriction under Irish rules for revisiting the deal expired.

Analysts said that an Aon-Willis deal might have trouble clearing antitrust hurdles and Aon’s shares plunged 16.7 per cent, while Willis’ shares slid 7.5 per cent, although both moves came in a market hit heavily by yesterday’s collapse in oil prices.

When asked about the timing of the deal, Mr Case told Reuters: “This is the time we move,” noting that he spoke to 250 senior colleagues yesterday who were “energised” by the deal.

“In a world of volatility, clients have needs around protecting assets,” Case said.

Willis shareholders will receive 1.08 Aon shares for each of their shares. The offer represents a premium of 16 per cent to Willis’ closing price on Friday.

Aon shareholders will own about 63 per cent and Willis investors about 37 per cent of the combined company. The deal is expected to add to Aon’s adjusted earnings per share in the first full year, with full savings of $800 million achieved in the third year.

Aon will keep headquarters in London and be led by Aon CEO Case and Aon CFO Christa Davies. Willis CEO John Haley will become executive chairman.

Aon and Willis put together insurance contracts for clients that involve a number of insurance providers, for anything from airlines to large sporting events.

Brokers also play a key deal-making role in the Lloyd’s of London commercial insurance market, which carries out much of its business face-to-face and insures specialist risks.

Aon and Willis also provide investment and employee benefits advice, and broker deals for reinsurers, who share part of insurers’ exposure to potential large losses like hurricanes, in return for part of the premium.

The combined entity will work across risk, retirement and health businesses. The deal will also allow the “new” Aon to offer clients services in areas like cyber, intellectual property and climate risk, executives said.

The deal follows Marsh’s purchase last April of British rival Jardine Lloyd Thompson for $5.7 billion.

“The insurers and reinsurers are unlikely to be happy about the deal given the scale of the two players coming together,” said analyst Ben Cohen at Investec.

The deal terms state Aon must pay $1 billion to Willis if the deal falls through.

Aon’s Davies said she was confident of getting all the necessary approvals for the deal.

“We have had great counsel on the topic of anti-trust, feel really good about it,” Mr Case said.

Credit Suisse advised Aon, while Willis was advised by Goldman Sachs.