Further details about liquid assets outside M4 data

The data series for liquid assets outside M4 are the building blocks from which users of the monetary statistics can create their own aggregates.

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Data are collected from a variety of sources:

  • UK-resident banks; all UK-resident banks report data directly to the Bank of England on the Form BT on a quarterly basis. Around 150 banks with eligible liabilities (BT£46) in excess of £400mn (positive or negative), or private sector holdings (BT items £2H and £3H or £29D) in excess of £1bn report data on a monthly basis. For those banks who do not report monthly, data are grossed up to provide a full population figure. Prior to September 1997, balance sheet data were reported on the BS form.
  • Channel Island and Isle of Man institutions; the data are sourced from the Isle of Man Treasury – Economic Affairs Division, Guernsey Financial Services Commission, and the Jersey Financial Services Commission.
  • UK-resident building societies; From January 2008 data from building societies are collected on the same basis as for UK-resident banks, on the Forms BT on a monthly basis (see the Statistics article on Transition of building society statistical reporting. Prior to this, data for building societies were collected by the Financial Services Authority.  These figures were based on a sample of societies, which were grossed up to achieve full coverage of the building society population in the published data.
  • BIS reporting area; data for the BIS reporting area are collected by the Bank for International Settlements (BIS) and are published in the BIS Quarterly Review.


Data are available quarterly from 1982 Q2 and monthly from April 1982.  The data are not seasonally adjusted.  Publication of data will usually occur on the 21st working day following the end of the period, in Liquid assets outside M4 (Table A7.1). 


Among assets not covered by these statistics are certificates of deposit issued by banks abroad (see Banks in the BIS reporting area, below), foreign currency commercial paper, foreign currency medium-term notes and other foreign currency short-term paper issued in the United Kingdom or overseas.  

In assessing the liquidity of those assets that are outside M4, users should remember that M4 itself contains some comparatively illiquid elements.  M4 contains deposits of any maturity with Monetary and Financial Institutions (MFIs: consisting of the central bank, other UK-resident banks and building societies), and some paper and other capital market instruments of not more than five years' original maturity.  But in practice, the majority of M4 is of less than five years' original maturity.

Banks in the BIS reporting area

The Bank for International Settlements (BIS) provides comprehensive data on international banking business conducted in the financial centres of the BIS reporting area. The number of countries within this area has increased over time (and currently stands at 40). Identification of the UK M4 private sector in these data is not entirely accurate.  Holdings of certificates of deposit are generally not covered by these statistics.

M4 private sector's holdings of foreign currency deposits

Foreign currency deposits held by the M4 private sector at MFIs in the UK or at institutions in the Channel Islands and Isle of Man (and at banks in the BIS area) may, at some point, be spent in the UK, overseas, or may represent a store of value relevant to UK economic activity.

Non-residents' sterling deposits

Deposits by non-resident banks with MFIs in the United Kingdom include deposits from central monetary institutions (i.e. part of other countries' official reserves), as well as deposits from commercial banks abroad. When combining series, users should be aware of potential double-counting: for example, sterling deposits at banks in the BIS area may in turn be placed by those banks as sterling deposits in UK banks or institutions in the Channel Islands and the Isle of Man (or indeed at other banks in the BIS area). 

Non-residents' sterling deposits, particularly those held by non-banks at MFIs in the United Kingdom, may, at some point, be spent in the United Kingdom; alternatively, they may be part of non-residents' global liquid assets, held temporarily or for a longer term in the United Kingdom as a store of value.

Sterling Treasury bills

Bills issued with an original maturity of six months or less are marketable and are likely to be considered liquid by their holders. 

Local government debt

Covers a variety of instruments, all with an original maturity of up to one year; in general, these instruments would probably be viewed as fairly liquid.

Certificates of tax deposit

These are not marketable; the return is greater when used to pay tax, so that their holders may not consider them liquid for other purposes.


The gilts data relate to marketable gilts, which are likely to be considered liquid by their holders. The degree of liquidity may be affected by the remaining maturity. The maturity split of total gilts is also available. There is also a small number of non-marketable (NILO) stocks in issue. Please see the section on 'other sterling debt' in the Explanatory Notes for the discontinued Table D1.1(Public Sector Net Debt) for a definition of NILO stocks.

Sterling commercial paper

Sterling commercial paper is marketable paper issued with maturities of up to and including one year. This series excludes paper issued by MFIs (because these issues are included in M4 if held by the M4 private sector and in the non-residents’ sterling deposits if held by non-residents). It also excludes paper held by MFIs. The series may include a small element held by non-residents but is likely to be held predominantly by the M4 private sector. 

Sterling medium-term notes

Sterling medium-term notes are marketable securities issued with original maturities of over one year and up to (and including) five years. They include both fixed and floating-rate notes. The series published here is the total of all issues except those by MFIs (which are included in M4 if held by the M4 private sector and in the non-residents' sterling deposits if identified as being held by non-residents). There are no data distinguishing MFIs', public or non-residents' holdings of this instrument; hence this series comprises all sectors' holdings.

Other sterling paper maturing within one year 

This series comprises all holdings of sterling bonds issued by the UK private sector and the non-residents sector of original maturity of more than five years, which are due to mature within one year. The majority are floating-rate issues, which may be considered more liquid than fixed-rate assets. There are no data distinguishing MFIs', public or non-residents' holdings of this instrument; hence this series comprises all sectors' holdings.

Residual maturity breakdown of gilts

The maturity breakdown cannot be allocated into sectors and hence both series cover all holders of gilts.

Sterling unused credit facilities

Coverage is incomplete - notably, the unused portion of credit card holders' limits is not included. Some banks report no unused facilities (although requests by borrowers to increase the credit limits are often met, and borrowers would probably expect them to be met). On the other hand, borrowers may have facilities with several institutions without intending to draw on them all simultaneously. Where a facility may be drawn in either sterling or foreign currency at the borrower's option, it is reported in foreign currency facilities - so that potential sterling facilities may be larger than the sterling facilities figures suggest. 

Valuation and Breaks 

Channel Islands and Isle of Man 

Until end-September 1997 about one eighth of the banking institutions in the Channel Islands and Isle of Man were treated as UK banks for statistical purposes. The remainder were treated as 'other financial corporations' (OFCs), whose coverage in the Isle of Man and in Jersey was only partial. The distinction between the two groups was made according to whether the institution had opted to comply with the Bank of England's monetary control arrangements. If 'opted in', an institution was treated as a UK bank for statistical purposes, and deposits by the M4 private sector with such an institution were included within M4.
Deposits with OFCs in the Channel Islands and Isle of Man, on the other hand, were not included in M4; but the deposits of these institutions with UK banks and building societies were included in M4. So, to the extent that these offshore OFCs took funds and re-deposited them in the UK, there was no 'leakage' from M4, although the sectoral breakdown recorded these deposits as being from the OFC sector rather than from the original source of funds. Adding deposits placed with these institutions by the M4 private sector to M4 thus introduced an element of double counting. 
The nature of financial activity in the Channel Islands and Isle of Man meant that the series for the M4 private sector's deposits probably included (before September 1997) substantial amounts placed by local companies and trusts on behalf of non-residents rather than on behalf of UK or local residents.
From end-September 1997, all institutions in the Channel Islands and Isle of Man are classified as non-residents. There are no longer any 'opted in' banks within the MFI sector. All business with the Channel Islands and Isle of Man has therefore been re-classified as non-resident. The data shown in the current series are collected from all banks and building societies in the Channel Islands and Isle of Man and are not comparable with the earlier data.

National Savings and Investments

The instrument breakdown for National Savings and Investments is no longer available from National Savings but the total is still available.

Building Societies transition to Bank of England reporting

Building societies' statistical reporting transitioned from the Financial Services Authority to the Bank of England on 1 January 2008, and some minor changes to the calculation of liquid assets have been implemented.  The effects of these have been removed from the flows data, and are small in terms of the amounts outstanding. 

This page was last updated 25 January 2018
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