Greek banks have been making headway in their bid to sell, write off or restructure billions of euros of bad debt accumulated during the last financial crisis.

On Monday, ratings agency Moody's upgraded the four largest Greek banks and gave them a positive outlook, saying the move was primarily driven by their improving asset quality and good prospects for further boosting their recurring profitability.

Piraeus Bank and Bain Capital were not immediately available for comment.

Piraeus Bank's portfolio of leasing contracts, dubbed project Sunshine, has a gross book value of about 530 million euros ($621 million).

Bain Capital is a multi-asset alternative investment firm.

In June last year Bain Capital Credit, a unit of the group, bought 1.6 billion euros of non-performing corporate loans from Greece's National Bank.

In 2018, Piraeus Bank agreed to sell a 1.45 billion euro portfolio of secured, non-performing business loans to Bain Capital Credit as part of moves to reduce its bad debts.

($1 = 0.8532 euros)

(Reporting by George Georgiopoulos; Editing by Mark Potter)