BRUSSELS (Reuters) - Aon will face a list of objections by the EU’s antitrust watchdog which it must overcome with concessions to proceed with its $30 billion bid for Willis Towers Watson, two people familiar with the matter said. The negotiations may derail Aon’s goal of closing the deal in the first half of the year unless it offers concessions in the coming weeks to stave off the charge sheet, the people said. The deal, announced a year ago, would create the world’s largest insurance broker, putting the merged entity ahead of world No. 1 Marsh & McLennan Companies Inc. The insurance industry has seen a wave of consolidation triggered by falling valuations, companies seeking to boost their business models, soaring COVID-19 related claims, and other challenges such as climate change. The European Commission, which suspended its investigation into the deal last month while waiting for Aon to provide requested information, is concerned the takeover may drive up prices and hold back innovation. The EU enforcer and Aon declined to comment. Aon shares extended losses and were down 0.5% while Willis erased earlier gains and were 0.6% lower by 1655 GMT. The Commission is readying a statement of objections, a charge sheet setting out possible competitive harm, the people said. Companies have about two weeks to respond and can request a closed-door hearing. Aon could stave off the charge sheet by offering concessions to address EU regulators’ concerns. The company has been in informal discussions about concessions but has not made an official offer to date, the people said. The EU enforcer wants Willis’ reinsurance business to be divested, which Aon has refused, and it is also looking to see if the companies may have to sell the global coordination of employee benefits broking and consultancy services, another person with direct knowledge of the matter said. Finding the right concessions that would satisfy large multinational clients, a key focus of the Commission’s questionnaires sent to rivals and customers, will not be easy, said a person who had received several such documents. “In order for a fourth competitor or third competitor to merge, they would need to replace Willis. Replacing Willis means replacing Willis’ footprints, their data analytic skill abilities, their cross risk capability, these are really expensive, hard things to build,” the person said. The deal has also fuelled concerns with the Australian antitrust watchdog which last month said it could significantly hurt competition in commercial risk, reinsurance and employee benefits broking and advisory services in Australia.