Insurance broker Aon has offered to sell assets in several EU countries and the reinsurance unit of takeover target Willis Towers Watson to gain EU antitrust approval for its $30 billion acquisition bid, a person familiar with the matter said on Monday.

Aon, which clinched the deal a year ago to create the world’s largest insurance broker ahead of Marsh & McLennan Companies Inc, submitted concessions to the European Union’s competition watchdog last Friday, an EU filing showed.

The sector’s biggest-ever deal comes as insurers grapple with rising claims and new challenges brought on by the COVID-19 pandemic and climate change.

Aon has proposed the sale of businesses in France, Germany, the Netherlands and Spain, including financial and professional lines and aerospace and cyber activities, the person said.

The package of concessions also includes corporate risk- broking activities in some other countries while a potential buyer examines those assets, the person said.

The European Commission, which did not disclose details of the concessions, set a July 12 deadline for its decision. It will seek feedback from competitors and customers before deciding whether to clear or block the deal or whether to seek additional concessions.

The EU enforcer earlier in the process demanded the sale of the Willis reinsurance business, which Aon had initially refused, while the business that provides consulting and administration services to companies on employee retirement and health schemes was also in focus, a source has told Reuters.