After injecting about 50 billion euros ($54 billion) to prop up Greece's four largest lenders in return for shares during the country's decade-long debt crisis which ended in 2018, state-controlled bank bailout fund HFSF started divesting its stakes last month.

Eurobank was the first to end the state's participation in its share capital in October, days before S&P Global became the first among the "big three" rating agencies to upgrade Greece to investment-grade status, which it lost in 2010.

On Monday, HFSF concluded the sale of a 9% stake in Alpha Bank to UniCredit and announced plans to sell a 20% stake in NBG.

A book-building process and a public offering for the sale of the NBG stake which started on Nov. 14 concluded on Thursday, with the final offer price set at 5.30 euros a share, the source said.

HFSF, which owns 40% in NBG, sold a total of 201,237,334 shares, raising more than 1 billion euros, according to Reuters calculations.

Earlier on Thursday HFSF said that orders at less than 5.30 euros would "most likely not be considered" for allocation, having announced that it planned to increase the stake on offer to about 22% from 20% on the back of strong demand.

Fidelity, Blackrock, Norges, Lazard, RWC and Allianz were among the investors who bought NBG shares.

($1 = 0.9211 euros)

(Reporting by Lefteris Papadimas; Editing by Toby Chopra)