Why MUFG, SMFG, Mizuho need not worry about liquidity stress

They have low dependence on confidence-sensitive market funding.

According to Moody's, the Japanese mega-banks have consistently demonstrated strong liquidity profiles. This strength is evident in their low loan-to-deposit ratios and their negative market funds ratios, both of which indicate a low dependence on confidence-sensitive market funding (see Exhibits 1 and 2 below).

Here's more from Moody's:

This situation provides the mega-banks with strong protection against liquidity stress, either from domestic or overseas sources. Given the strong preference of Japanese customers for deposits, and the structurally weak state of loan demand in Japan, we expect this trend to continue.

While Japan’s declining and ageing population could pressure overall growth in deposits, we believe that regional financial institutions will be primarily affected. The three mega-banks – with their very strong nationwide presence, especially in metropolitan areas – are likely to be less affected.

At the same time, Japanese corporates have a tendency to hoard cash that finds its way into the banking system as deposits. With few opportunities to invest excess cash, the liquidity positions of the mega-banks are likely to remain unchanged.