Fosun, controlled by billionaire entrepreneur Guo Guangchang, has been one of the most aggressive foreign dealmakers in Portugal since mid-2014, when the country was still under an international bailout after a debt crisis.

"Fosun is not selling its stake in Millennium bcp. It is not for sale," a Fosun spokesperson in Lisbon told Reuters. Fosun is the largest shareholder in Millennium bcp, followed by Angolan state oil company Sonangol with a stake of 19.5%.

Bloomberg reported on Tuesday that Fosun was reviewing some investments in Portugal as a way to raise money to repay debt.

Fosun also has 85% of Portugal's largest insurance firm Fidelidade, which in turn owns the country's leading private healthcare group Luz Saude.

A Citigroup report on Tuesday said Fosun planned to sell 50 billion to 80 billion yuan ($7 billion-$11 billion) of non-core assets within the next 12 months. It said Fosun considered its listed pharmaceutical, retail and tourism businesses, as well as Fidelidade, as core assets.

A Fidelidade spokesperson said Luz Saude was "a strategic asset and essential for the growth of the insurance group" and was not for sale.

Credit rating agency Moody's downgraded Fosun by one notch on Tuesday and revised its outlook to "negative" amid concerns over the firm's accelerated asset sales.

($1 = 7.1800 Chinese yuan renminbi)

(Reporting by Sergio Goncalves; Editing by Andrei Khalip and Alexander Smith)

By Sergio Goncalves