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Market Operations under the Three-tier System-- Explanation Using the Reserve Demand Curve Model *1 --

May 27, 2022
Takuto Arao*2
Financial Markets Department
Bank of Japan


In Japan's money markets, negative interest rate transactions prevail under the three-tier system applied to the financial institutions' current accounts held at the Bank of Japan. This paper explains the mechanism of short-term interest rate formation under the three-tier system and the concept of market operations using a simple reserve demand curve model.

Under the three-tier system, in which current deposits are divided into three tiers and different interest rates are applied to each tier, financial institutions have an incentive to conduct money market transactions for arbitrage purposes depending on to which tier their outstanding current account balances fill up prior to money market transactions. The Bank realizes negative interest rates consistent with yield curve control by taking steps so that the "hypothetical policy-rate balance (the policy-rate balance that remains assuming that arbitrage transactions have taken place in full), " is maintained at a certain level.

The shape of the reserve demand curve is considered to be downward sloping around the boundaries of each tier due to the uncertainties over future course of current account balances. The shape and position of the reserve demand curve will change depending on the degree of the uncertainties and other factors such as the use of Special Operations in Response to COVID-19 and various loan support programs. Short-term interest rates also change when arbitrage transactions are not conducted in full due to market friction. It can be interpreted that the Bank influences on short-term interest rates by changing the reserve demand curve and the reserve supply curve through setting the Benchmark Ratio and carrying out market operations based on the information about these factors.

  • The author is grateful to Ms. Junko Koeda, Mr. Toshifumi Nakamura, Mr. Motoharu Nakashima, Mr. Teppei Nagano, Mr. Ryohei Oishi, Mr. Norihisa Takeda, Mr. Yoichiro Tamanyu, Mr. Shinichi Wada, and the staff members of the Bank's Financial Markets Department and other departments for the useful advice and comments. Any remaining errors are the responsibility of the author. The content and opinions expressed in this paper belong to the author and do not necessarily represent the official views of the Bank of Japan.
  1. *1The supply and demand in the actual money market applies to the current accounts of financial institutions at the Bank. However, in this paper, the terms "reserve demand curve" and "reserve supply curve," which are commonly used in academic papers, will be used.
  2. *2Financial Markets Department, Bank of Japan
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