A senior citizen in Hubei displays his pension deposit book.?[ Photo/Xinhua]

China's pension deficit will take up 10 percent of the country's annual expenditure by 2050 even if the government raises the retirement age, highlighting the necessity of reforming pension fund management, a report showed Thursday.

By 2017, the pension fund would face a deficit of 0.2 percent of annual gross domestic product, rising to 5.5 percent by 2050, according to a report co-authored by Ma Jun, chief researcher at Deustche Bank, and Fudan University researchers.

"If the age of retirement is raised by seven years in 2050, the subsidies required to make up the pension deficit will amount to 9.9 percent of the fiscal expenditure," the report said. "So it must be complemented by other reforms."

The report suggested the government start postponing retirement by one year in each five-year period starting 2020, and to transfer state-owned equities to the pension fund. To ensure a sustainable capital supply, the pension fund should only be allowed to use dividends from the shareholdings to replenish capital, the report said.

If retirement is delayed and 80 percent of the state-owned listed shares were to go to the pension fund, the annual gap may amount to 1 percent of GDP instead of 5.5 percent by 2050.