Consultancy giant Aon today pulled out of discussions regarding a potential merger with its rival Willis Towers Watson (WTW).

In a statement, it confirmed that it had “considered potential opportunities with regards to WTW” as part of regular evaluations of return on invested capital.

It blamed “media speculation” for its disclosure at the very early stage in the “consideration of a potential all-share business combination”.

However, it also stated that it “reserved the right within the next 12 months to set aside this announcement where so permitted under Irish takeover rules”.

Aon’s London-based head office had already issued a statement on Tuesday in response to a report by Bloomberg, saying it had to make its intention public under Irish law after the newswire reported the discussions, as WTW is headquartered in Ireland.

In its first statement, Aon highlighted that there was no certainty about a takeover or merger, or what form it might take.

Aon and WTW are internationally known as, respectively, the second-largest and third-largest providers for insurance advice and risk management, and a merger would bring them close to industry leader Marsh and McLennan, the parent company of Mercer.

The two companies are also dominant players in pensions and human resources services. In the UK, along with Mercer, they are the biggest investment consultants and fiduciary managers.

WTW and Aon are both listed in New York, where WTW’s shares rose by 5% yesterday, taking the company’s market value to more than $22bn (€19.5bn).

In contrast, Aon’s market capitalisation fell almost 8% to $40bn.

Several commentators highlighted potential competition problems as a result of a merger. One analyst at Wells Fargo predicted that both companies would be forced to sell their overlapping business units, “as there are many areas where a combination of the two firms would lead to too much concentration in the market”.

WTW was created by the $8.6bn merger of Willis Group with Towers Watson in 2016. Towers Watson, in turn, was created by the merger of Towers Perrin and Watson Wyatt in 2009.

Willis Towers Watson has so far declined to comment on a possible takeover.