High Quality Content by WIKIPEDIA articles! The official cash rate (OCR) is interest rate paid by banks in the overnight money market in Australia and New Zealand. Through the regulated use of exchange settlement accounts, a central bank is able to adjust the interest rates of a nation`s economy. The OCR cannot be changed by transactions between financial institutions as this does not change the supply of money, only its location. Only transfers between the central bank and an institution can affect the cash rate.