Asahi Bank and Daiwa Bank announced Friday that they have reached a basic agreement to join forces under a single holding company in a bid to survive as stock price tumbles eat away at their capital.

Asahi, with assets of 30.3 trillion yen, will ally with Daiwa and two smaller Kansai regional banks by coming under a Daiwa-dominated holding company based in Osaka by the end of March. Daiwa is half Asahi's size in terms of assets with 15.5 trillion yen.

"Asahi Bank's addition means more expertise, especially in retail banking, a sector in which Asahi specializes," said Daiwa Bank President Yasuhisa Katsuta at a news conference Friday at the bank's headquarters in Osaka.