Asahi Bank became a wholly owned subsidiary of Daiwa Bank Holdings Inc. on Friday, creating the nation's fifth-largest banking group with more than 50 trillion yen in assets.

Asahi Bank joined Daiwa Holdings, which was established in December through a merger of Daiwa Bank and two regional banks in western Japan -- Kinki Osaka Bank and Nara Bank -- in a bid to create a "super-regional bank" to survive an increasingly competitive marketplace dominated by some of the world's largest megabanks.

Slumping share prices and high levels of bad debt continue to eat away at banks' capital and their reserves.