NBG is offering 58 new shares for every 100 shares of Eurobank. Once the share exchange is completed, NBG shareholders will own 75 percent of the combined entity, with Eurobank shareholders owning the rest.

At current prices, NBG's market capitalization is 3.2 times that of Eurobank.

Eurobank, advised by Barclays, Deutsche Bank and Goldman Sachs International, said in a news release that it would consider the proposed merger "in a constructive spirit."

Eurobank shareholders representing 43.6 percent of the bank's stock had accepted the offer, said NBG, which is advised by Credit Suisse.

NBG Chairman George Zanias and Tourkolias would keep the same posts in the combined group, NBG said.

The bourse suspended trading in the shares of National Bank and Eurobank earlier on Friday following a media report of the merger talks, which sent Eurobank's shares up 5.5 percent to 1.15 euros and National Bank's 4.5 percent to 2.1 euros, to value the two at around 2.6 billion euros ($3.4 billion).