The sale is probably the last one by a major bank, making it positive for the banking stocks overall.
The bank has a clear strategy focusing on consumer loans charging higher interest rates. That should help raise its profitability.
That means Tokyo Star is seen as an average regional bank and that's why the shares fell below the offer price.
Sumitomo Mitsui stock outperformed even after the offer was announced. That means investors are confident in the bank's business outlook.
Investors already learned about the recovery in Japan's banking industry and the Mizuho sale gives them another investment opportunity.
They need to change their corporate culture to fit into the local market.