The Chinese government has been considering the sale of Anbang's overseas real estate and insurance assets, which include Belgian insurer Fidea, since it took control of the troubled company in February.

JPMorgan won the mandate after Anbang asked banks to pitch for a role in August, the sources said.JPMorgan declined to comment. A Vivat spokesman referred questions to Anbang.

An Anbang spokesman said on Wednesday evening the review of Vivat had not been completed and a final decision would be based on the results of the review. He declined to comment further.

Sources said in July the insurer was looking to offload overseas properties worth about $10 billion to shore up its balance sheet as part of a government-backed rescue.

UBS and China's CICC have wider roles advising Anbang on its restructuring. Sources said they were not handling Vivat's sale as Anbang wanted independent advice on its European disposals.

Vivat on Wednesday reported a first-half underlying result of 115 million euros, with a Solvency II ratio of 167 percent and a book value of 3.35 billion euros.

Two Dutch insurers, Aegon and ASR, have said they were aware Vivat was preparing a sale and would consider bidding.

ASR could pay around 1.4 billion euros for Vivat, ABN Amro analyst Cor Kluis said in an email on Wednesday.

Anbang bought Vivat -- the insurance arm of the defunct SNS Reaal, nationalized by the Dutch government in 2013 -- for a nominal 1 euro and a cash injection of 1.35 billion euros.

However, Anbang's foreign expansion plans suffered a setback in May when former chairman Wu Xiaohui was sentenced to 18 years in prison for fraud and embezzlement. He is appealing the conviction.

In April, the Chinese government gave Anbang a 60.8 billion yuan ($9.67 billion) capital injection and began selling its assets.

The two sources said that Dutch insurers Aegon and ASR were considered the most likely buyers for Vivat as a "deal of synergies" made more sense than a buyout.

The Dutch central bank supports consolidation of the Dutch insurance industry, and last year quickly approved a takeover of Delta Lloyd by NN Group.

Vivat's operations include personal life insurer Reaal, corporate life and pension insurer Zwitserleven and investment arm Actiam, with more than 54 billion euros of assets under management.

(Additional reporting by Arno Scheutze, David French and Pamela Barbaglia; Editing by Louise Heavens and Darren Schuettler)

By Sumeet Chatterjee, Kane Wu and Toby Sterling