State Bank of India on Monday said it aims to retain at least 25-30 per cent of the Rs 25,000 crore (Rs 250 billion) Resurgent India Bonds proceeds by launching an "instrument" having both fixed and floating rates in September.

"Our efforts are to retain 25-30 per cent of the RIB proceeds back to the system," SBI chairman A K Purwar said after a branch inauguration at Dasna near Ghaziabad.

He said the bank was planning to come up with an "instrument" which will offer an option to the RIB holders to park their money after the bonds mature in October.

"The instrument will have both fixed and floating rates," the SBI chief said.

The bank plans to hold roadshows in September end for wooing investors of Resurgent India Bonds to put their money in a special deposit scheme, which is now being examined by the Reserve Bank of India.

The bank is watching the movements in London inter-bank offer rate and plans to peg the rate of return on its special scheme at the end of next month.

SBI hopes to get the RBI nod for its special deposit scheme within a week or two.

Asked whether the rupee depreciation in the last five years would have any impact on the returns to NRIs, he said, "The exact amount of depreciation could be calculated only at the time of redemption."

All arrangements have been made and it is unlikely that there would any impact on the domestic interest rates.

"I am a proponent of a stable interest rate regime and soft interest rate bias will continue," Purwar added.