ATHENS, March 26 (Reuters) - National Bank (NBG), one of Greece's four largest lenders, has agreed to sell its insurance unit to private equity group CVC Capital, two banking sources close to the process said on Friday.

"There is agreement to sell a 90% stake in National Insurance to CVC Capital," one of the bankers told Reuters, declining to be named. "There will be announcements on the deal later on Friday."

Private equity group CVC Capital, with $109 billion of assets under management, was the only bidder for NBG's wholly-owned insurance unit and submitted a binding bid one year ago.

The sources did not reveal the price of the transaction.

Reuters reported last month that NBG had completed talks to sell the insurance subsidiary to CVC Capital and that the bank's management and board of directors backed the sale.

The divestment is part of NBG's EU-approved restructuring plan to shed non-core assets. The bank has sold assets in the Balkans, including operations in Bulgaria, Albania and Romania, and Turkey, downsizing to focus on its core domestic banking business.

NBG, 40% owned by the Hellenic Financial Stability Fund (HFSF), Greece's bank rescue fund, was due to hold a board meeting later on Friday ahead of a scheduled full-year 2020 earnings announcement.

HFSF, which has sought the advice of Morgan Stanley and Deloitte on the deal, also backs the sale, the other banker said.

HFSF was not immediately available for comment. National Bank declined to comment.

NBG had tried unsuccessfully to sell the insurance unit in previous years. In 2018 it ended talks with Shanghai-based Gongbao Group to divest a majority stake in National Insurance.

Before that, a deal to sell 75% of the unit to U.S. fund manager Calamos Investments and EXIN Partners for 718 million euros ($871.72 million) turned sour after a legal row erupted between the two buyers. (Reporting by George Georgiopoulos; Editing by Susan Fenton)