They focus primarily on asset management for private clients and do not publicly offer to accept savings deposits.
But while loan business may be sparse, savings deposits are ample.
Consumer loans are also made using savings deposits, which are not subject to reserve requirements.
It has 45 branches and assets totaling $6 billion, two-thirds in savings deposits.
These analysts point out that the plan is based on highly optimistic assumptions about the future course of interest rates, inflation and savings deposits.
The Bush plan also calls for using insurance premiums on savings deposits to build the fund's reserves to $9 billion by 1999.
They argue that most Japanese investors do not like risk and will probably roll over their postal savings deposits.
Such defaults in the 1930's brought on bank failures that wiped out the savings deposits of many Americans.
Interest rates on savings deposits were over 15% at a time when the industry was invested in long-term mortgages charging about 8%.
In addition, higher interest rates for savings deposits held by overseas Chinese will be canceled, the central bank announced.