ATHENS, May 16 (Reuters) - The U.S. Commerce Secretary has backed a bid by an American-Dutch consortium to buy the insurance arm of Greece's National Bank, saying a deal could help U.S. investment flows to the troubled Mediterranean country.
U.S.-based Calamos Investments, which has $20 billion under management, and EXIN Partners, a Netherlands-based investor focused on insurance, reinsurance and asset management, are bidding for at least 75 percent of National Insurance.
Calamos-EXIN is competing against three interested Chinese groups: Fosun, Shanghai-based Gongbao and Wintime.
Greek media have reported the deal, which has to close by the end of 2017, could be worth about 800 million euros ($882 million).
U.S. Commerce Secretary Wilbur Ross wrote a letter to Greek Prime Minister Alexis Tsipras that called for a transparent sale, a senior banker told Reuters. "It is a strong letter," he said.
"The Secretary is fully supportive of the Calamos-EXIN bid, saying it would be a good start towards improving U.S. investment flows to Greece," said the banker, who asked not to be identified.
Ross's letter was copied to the Greek bank association, National Bank's (NBG) management and the central bank, Bank of Greece, the banker said.
Founded in 1891, National Insurance is Greece's oldest insurer and provides life and non-life insurance products. The company had a 16.6 percent share of the market last year and 2015 net profit of 98 million euros ($108.11 million).
NBG, the country's second-largest lender, is selling the unit as part of a restructuring plan approved by the European Union to exit non-banking operations and focus on core banking.
Other Greek banks have been divesting non-core assets and foreign subsidiaries. Eurobank has sold an 80 percent stake in its insurance unit Eurolife to Canada's Fairfax Financial Holdings for 316 million euros.
Another banker close to the procedure confirmed Ross's letter had also been sent to NBG management, saying the bank's intention was to complete the sale by the end of the month, although it was not certain that it would be wrapped up by then.
NBG is being advised by Morgan Stanley and Goldman Sachs.
Calamos Investments CEO John Koudounis said this month Calamos-EXIN had presented a hard-to-match offer, but did not give details. He said other Greek-American investors interested in Greece were watching closely.
Exin Partners bought insurer AIG-Greece from AIG in December, partnering with Canellopoulos Adamantiadis Insurance Agency.
$1 = 0.9065 euros Editing by Edmund Blair