The state will need to inject 11.26 trillion yen into 33 government affiliates over the next 80 years to keep them in operation, an advisory panel to the finance minister estimated Wednesday.
Funds for special public corporations come mainly from the "zaito" fiscal investment and loan program, which is mostly financed by postal savings and public pension insurance funds.
According to estimates by the Fiscal System Council, Japan Highway Public Corp. -- the largest among the 33 public firms -- will swallow 3.36 trillion yen in taxpayer money over the next 51 years to complete ongoing projects and those currently in the pipeline.
Japan National Oil Corp., coming in second, will require 1.82 trillion yen over the next 21 years, the estimate reveals.
The costly public entities are on a list released last week by a government task force of public corporations to be reviewed for possible disbandment.
Estimates were also made by taking into account fluctuations in interest rates and earnings.
If interest rates rise 1 percent from current levels, for example, Housing Loan Corp. would need 1.56 trillion yen in additional public funds. A 10 percent fall in the revenues of Japan Highway Public Corp. would require 2.8 trillion yen more.
The zaito is often dubbed the nation's "second budget" because of its size. For the current fiscal year, 32.54 trillion yen has been earmarked for the program.
The government has long been criticized for lacking concern over how efficiently the funds are used by special public corporations.