The Mutan Interest rate is the Uncollateralised Overnight Call Rate in Japan . It is the reference rate for JPY overnight unsecured transactions in the Japanese market. It was launched in April 1996 and it is the main tool for the Bank of Japan ‘s monetary policy .
Bank of Japan Publishes a provisional rate, rounded to three decimal places,  every business day around 5:15 p.m. JST (or 6:15 p.m. JST for the last business day of the month).  A final result is published the following business day around 10:00 JST. The results published contain weighted-average , highest, and lowest rate in the business day. 
- Federal funds rate
- Interbank lending market
- Jump up^ “Change in the smallest tick in uncollateralized overnight call rate” . Bank of Japan . 6 September 2001 . Retrieved 25 June 2012 .
- Jump up^ “Revision of the publication of” Uncollateralized overnight call rates (average) ” . Bank of Japan . 6 September 2002 . Retrieved 25 June 2012 .
- Jump up^ “Release of the Data Related to the Bank’s Operations and Uncollateralized Overnight Call Rate” . Bank of Japan . 6 May 2004 . Retrieved 25 June 2012 .