European regulators on Friday gave conditional approval to Aon PLC’s acquisition of rival brokerage Willis Tower Watson PLC, but the deal still faces major hurdles in the United States where an antitrust trial over the transaction is slated for November.

The European Commission’s approval is contingent on Aon completing its previously announced deal to sell various Willis assets to smaller rival Arthur J. Gallagher & Co. The sale to Gallagher would reduce the combined Aon-Willis’ influence in various market sectors and bolster Gallagher’s capabilities in reinsurance broking and commercial risk brokerage and “improve its footprint” in Europe, a European Commission statement said.

“The remedy package accepted by the Commission ensures that European companies, including insurance companies and large multinational customers, will continue to have a good choice and good services when selecting a broker suitable for their needs,” said Margrethe Vestager, the Commission’s executive vice president in charge of competition policy, in a statement.

European regulators opened a full-scale investigation into the deal in December 2020. The acquisition, which was announced in March 2020, would potentially reduce competition for brokerage services in several key areas, the investigation found, including commercial risk brokerage services to large multinational companies based in Europe, reinsurance broking and the provision of pension administration services in Germany.

In addition to selling various reinsurance broking assets, specialty business in the United Kingdom and brokerage operations in France, Spain, Germany and the Netherlands to Gallagher, Aon agreed to sell various German pension and investment consulting businesses to London-based consulting firm Lane Clark & Peacock LLP. 

Antitrust regulators in the United States, though, have significant objections to the deal and filed suit against Aon and Willis last month. The Department of Justice’s suit identified several areas of competition concern, including the provision of health benefits plans and property/casualty coverage to large customers.

The trial is scheduled to start proceedings Nov. 18-23 and resume Dec. 20-22.