Costopoulos told a press conference that "we are creating the biggest Greek bank ... It is a major step forward in the rationalisation of the (banking) system. We always said the (domestic) banking system has too many banks," he said.
Costopoulos added that a "European-size" bank was being created, the 22nd or 23rd in ranking in Europe, due to "the first foreign investment in this country in many years, the investment of Qatar, which comprises a vote of confidence for Greece".
From all aspects, he continued, "it is a very important step".
Eurobank president Timos Christodoulou, in turn, called the new bank to emerge from the merger a "basis for the recovery of the economy when we exit the crisis, and a developmental vehicle for Greece", adding that Qatari participation will serve as an example for other economies.
Christodoulou said the new credit organisation will be a model for other similar initiatives, "so that we can develop with a dynamism that characterises Greece".
Alpha Bank CEO Dimitris Mantzounis said the "key to success" was that the two banks "speak the same language, share the same principles, the same values", adding that the new bank will be top in Greece in all banking activities.
"We have the most desired international shareholder with us, and aspire to synergies of 650 million euros over the next three years," he added.
Bank of Greece Gov. George Provopoulos called the merger deal "the first landmark step in the process of redesigning the Greek banking map".
The Bank of Greece (BOG) chief added that the substantial reinforcement of the capital of the new bank, the friendly agreement between the two partner banks, the participation of a powerful foreign investor and the exploitation of synergies constitute an optimistic prospect for the Greek economy and banking system.
Provopoulos reiterated that such strategic moves contribute decisively to boosting the competitiveness of the banking system and fiscal stability.
Greek government vice president and Finance Minister Evangelos Venizelos welcomed the deal as a "positive development that shows the dynamism and prospects of the Greek banking system", adding that the initiative proves that the current crisis can serve as an opportunity for structural moves that give impetus to the fiscal sphere and also the sphere of the real economy.
He also described as significant the participation in the new banking scheme of Qatar "which is investing in Greece and sending internationally a message of confidence in the potential of the Greek economy".
Earlier, Development, Competitiveness & Shipping minister Mihalis Chryssohoidis said the merger of the two banks, when completed, will give a new mark to the market inside and outside Greece, the mark of confidence that the Greek economy has the prerequisites for recovery and viability.
Replying to a press question, the minister said that in the coming period the country will require a healthy banking system that will provide the necessary liquidity to the market.
Under the terms of the merger deal, Eurobank biggest share-holders, the Latsis family, and Alpha Bank's major shareholders, the Costopoulos family, will hold 13 percent and 4 percent stakes, respectively, in the new bank, while Qatar's Paramount Services Holding will have a 17-percent stake.
Main opposition ND: Merger a 'correct strategic move'
Main opposition New Democracy (ND) leader Antonis Samaras on Monday welcomed as a "correct strategic move" the planned merger of Greece's second and third largest banks that was formally announced earlier in the day.
The EFG Eurobank-Alpha Bank merger aiming to create a new bank is a "correct strategic move that contributes to the stability of the Greek banking system", Samaras said, adding that "it is the response to the challenges faced today by the Greek banking system chiefly due to the government's inadequacy".
Samaras said that the creation of a "powerful banking group, with a strong presence both inside and outside Greece and with high capital adequacy rates, also addresses a restructuring of the Greek debt and a possible increase in risks due to the big recession".
He stressed that the stability of the Greek banking system is a necessary prerequisite so that government and credit institutions, with the proper initiatives that, unfortunately, are lacking today, may channel the required liquidity to the markets for re-starting the real economy and bringing the country out of the crisis.