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# Explanation of "Monetary Base Statistics"

May 2013
Bank of Japan
Research and Statistics Department

## Basic information

Frequency of compilation : Monthly basis

Time of release : 2nd business day of the following month

Commencement of data : January 1970 (average amounts outstanding), July 1996 (amounts outstanding at end of period)
There is no continuity between the figures until March 1981 and those from April 1981.

## 1. Definition

The monetary base is the "Currency Supplied by the Bank of Japan" and is defined as follows.

Monetary base = Banknotes in Circulation + Coins in Circulation + Current Account Balances (Current Account Deposits in the Bank of Japan)

## 2. Notice on usage

1. 1) The "Banknotes in Circulation" and "Coins in Circulation" in the monetary base include cash (banknotes and coins) held by financial institutions, while "Currency in Circulation" in the Money Stock Statistics does not. This is because the former is defined as the "Currency Supplied by the Central Bank," while the latter is defined as the "Currency Supplied to the Economy from the Financial Sector as a Whole (including the central bank)" in addition.
2. 2) The definitions of the monetary base
New Basis (April 1981 -) = Banknotes in Circulation + Coins in Circulation + Current Account Balances (Current Account Deposits in the Bank of Japan)
Old Basis (- March 1981) = Banknotes in Circulation + Coins in Circulation + Reserve Balances
• In order to indicate "Currency Supplied by the Bank of Japan" more precisely, "Reserve Balances" has been replaced by "Current Account Balances (Current Account Deposits in the Bank of Japan)" which includes deposits by institutions not subject to the Reserve Requirement System (tanshi companies <money market brokers-cum-dealers>, securities companies etc.)
1. 3) Method of adjusting the effect of changes in the reserve requirement rate
Reserve balances (reserve requirement rate change adjusted) = Reserve balances of the month * (Average effective reserve requirement rate of base period / Rate of comparison period)
Base period:
the following month of the month when the latest reserve requirement rate change occurred. (The current base period is November 1991)
Comparison period:
the months when the latest reserve requirement rate
change occurred---the same month
From the base period and onward---base period
other months---the previous month of the month when the reserve requirement rates is changed.
Average effective reserve requirement rate:
Required reserve balances / Liabilities subject to reserve requirement
figure : example
Example (base period: June) January* February March April May June* July +++
Reserve balances 100 120 80 150 160 120 130 +++
Base period
(effective reserve rate)

(1.1)
+++
Comparison period
(effective reserve rate)

(1.6)

(1.5)

(1.2)

(1.1)
+++
Reserve balances
68 88 58 110 146 120 130 +++

* Reserve requirement rate changed in January and June.

- After the base period, figures adjusted to the changes in the reserve requirement rate are equal to those unadjusted because the base period and comparison period are the same month. In other words, they are adjusted retroactively when the reserve requirement rate changes.

1. 4) Reserve Balances for the last two months are preliminary figures.
2. 5) Notes on usage
Regular revision
Every February: the seasonally adjusted data are revised from the beginning of the data.
Irregular revision
If an error is discovered in the reported data or in the compiling process, the data are revised immediately. In principle, the data are retroactively revised, and are announced on the closest release date from when the data correction is finished.