Old dogs, new tricks:
adapting central bank
balance sheets to a world of
digital currencies - remarks
by Andrew Hauser
Given at Federal Reserve Bank of New York and Columbia SIPA
Workshop on 'Monetary Policy Implementation and Digital Innovation',
New York
01 June 2022
Speech
Introduction
The explosion of interest in digital currencies poses deep and challenging policy questions
on everything from monetary and financial stability, to privacy, competition, money
laundering and social inclusion. Public authorities are evaluating the arguments for and
against introducing their own Central Bank Digital Currencies (CBDCs).1 And in the
private sector there's a lively debate about what it might take to make so-called
'stablecoins' genuinely stable.
there's been less discussion about
Up to now, though, how central bank balance sheets
might need to adjust to support the safe and effective provision of fiat-based digital
currencies. This workshop is therefore well timed.
I will focus my remarks today around five main messages.
1. Retail CBDCs could be a big deal for central bank balance sheets
Let's start with retail CBDC -
a central bank liability, in digital form, held directly by
individuals, and used to make day to day payments. Many of the raw ingredients of a
CBDC are already familiar to central banks: individuals can already hold our liabilities, in
the form of physical banknotes; and we already provide digital liabilities, albeit to only a
few depositors (predominantly banks).
The new thing would be to combine those ingredients together, at scale.
The question of whether to do so is complex, and beyond the scope of my remarks today.
The UK will publish a consultation on this issue later this year. But the implications for
central bank balance sheets will also depend heavily on how any CBDC is designed: on
who can hold it, where it can be used, how much can be held, and whether it is
interest-bearing (Table 1).
Source: Bank of England
CBDC close to today's banknotes
Design choices that placed the economic features of
might have relatively limited implications for central bank balance sheets, at least in normal
economic conditions. Choices that positioned the economic features of CBDC closer to
today's retail commercial bank deposits could have a more material
impact.
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To give some sense of potential scale, Chart 1 compares two stylised benchmarks the
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stock of banknotes; and 20% of retail commercial bank deposits2 to the size of central
bank balance sheets between the period before the Global Financial Crisis and today. In
the UK, the upper end of that benchmark range is nearly half the size of the
Bank of England's
balance sheet today, and six times that in 2007.
Individual central banks' published data,
Sources: IMF, Bank calculations.
Those are big numbers.
aren't
But they unprecedented in the history of central banking. In the UK, even the top
end of the range in Chart 1 would still leave the stock of publicly-provided means of
payment at around the levels seen in the mid-20th century (Chart 2). This underscores the
point that, while the technology for any future CBDC may be new, the use of the central
bank balance sheet to provide state-backed transactional money would not be: indeed, it
is one of the oldest functions of central banks.
Sources: Bank of England, IMF.
2. Stablecoins that are truly stable may have much the same impact
As public authorities reflect on the case for CBDCs, private sector providers have been
'stablecoins', which claim to be pegged to the value of fiat currencies.
developing so-called
I say 'claim', because recent weeks have
suggested such promises may be less than fully
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credible. The value of TerraUSD once one of the larger 'stablecoins' by market
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capitalisation fell to zero in just a few days. And Tether, sometimes asserted to be the
backbone of the cryptocurrency ecosystem, lurched precariously below parity for a period
'stable' they are
(Chart 3). These gyrations have multiple causes. But not. And the lack of
complete, real time, information on the assets backing the promise of convertibility,3
means that holders of such coins must accept at least the possibility of finding themselves
badly out of pocket.
warnings may be
Such 'buyer beware' sufficient for coins that are only in niche use. But
they cannot be enough for any that reach systemic scale. And that is why the
Bank of England's
Financial Policy Committee has recommended that, in the UK, any
stablecoin that reaches systemic size should also meet standards equivalent to those
expected of commercial bank money.4 In practice that is likely to mean being issued by a
bank, or by a non-bank that: is subject to rigorous central bank regulation and
supervision;5 provides coinholders with a robust legal claim; is insolvency remote; and
transparently backs its coins with a precisely defined set of high quality and liquid assets.
Source: Bloomberg Finance L.P. Digital Asset Research, Inc.
It's too soon to say what those assets should be. But, to take
one example proposed by
some, if a systemic stablecoin were required to be fully backed by deposits at the central
bank, the implications for central bank balance sheets could be very similar to CBDC
a 'narrow bank'
(Chart 4). This would also be the case if chose to issue its own tokenised
deposits and put all the proceeds into holdings at the central bank. Indeed, arguably any
stablecoin with a credible link to fiat currency relies ultimately on settlement in central bank
money. Of course, that does not mean that it is central bank money: even fully-backed,
regulated stablecoins would remain the liabilities of private sector companies, and hence
pose a range of risks not associated with CBDCs.
3. Digital currencies may alter the transmission mechanism for monetary policy
A key unknown in assessing the impact of digital currencies lies in judging the extent to
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which they may affect the flow, and pricing, of money and credit in the economy which in
turn has implications for the transmission mechanism for monetary policy. When a bank
creates a new loan, it must retain or attract sufficient deposits to fund it.6 Digital currencies
do not fund credit creation, but they do increase the competition for, and hence the cost of,
deposits, with knock-on implications for the price and availability of credit.
The size of these effects will depend heavily on the eventual design of any systemic digital
currencies, their attractiveness relative to bank deposits, the availability and price of
ability to substitute
alternative funding sources for banks, and borrowers' between types of
credit. It is not a foregone conclusion that these effects will necessarily be large. Indeed,
an illustrative scenario published by the Bank of England in 2021 suggested that the
steady state impact could be quite modest, with lending rates rising only slightly, and credit
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provision falling by a little over 1% though varying the assumptions can generate
somewhat larger results (Chart 5).
"New Forms of Digital Money"
Source: Bank of England Discussion Paper:
More serious disruption to credit supply could occur if deposits transferred into digital
currencies in an unexpectedly rapid or disorderly way, for example during a stress event.
But a range of design choices, including potential holding limits, could in principle be
deployed to deal with such situations. And banks suffering sudden deposit outflows may
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also, as now, draw on market-wide central bank liquidity insurance facilities7 though the
pricing of such facilities, and their implications for encumbrance, make them less well
suited to providing long-term structural support.
A particularly sensitive question is whether central banks may seek to use CBDCs, or
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other forms of digital currency, to enhance monetary policy implementation e.g. by
overcoming the effective lower bound to interest rates, or injecting liquidity directly into the
retail sector.8 But there is no sign that central banks are thinking of digital currencies in
this way. The Bank of England, for example, has stressed that any CBDC would
complement, not substitute for, physical cash.9
4. Digital currencies may affect the way central banks deliver monetary control
Over and above any impact that digital currencies may have on the transmission
mechanism, they could also have implications for how central banks achieve 'monetary
control': i.e.
ensuring that short term market rates are aligned with official rates chosen by
policy makers.10
Today, most central banks achieve this control by ensuring they at least meet banks'
demand for central bank reserves, and remunerate those reserves such that market rates
trade near or at the official rate. Other things equal, flows into digital currencies issued or
backed by the central bank, will drain reserves from the system. That could complicate
monetary control if it causes banks to bid up for reserves, pushing up on short term market
rates relative to official levels.
- 'autonomous factors' -
Such effects ingloriously known as in central banking jargon are
nothing new. Increases in physical banknotes or government deposits, for example, also
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drain reserves and scaling that historical variation by the sort of estimates for CBDC size
shown in Chart 2 suggests that day to day variation in CBDC demand would not pose
materially greater uncertainty (the orange bars in Chart 6). Sharper and less predictable
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inflows, e.g. during a period of stress proxied in the purple bar in Chart 6 using the
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extreme tail of existing autonomous flows could however drive rather larger volatility.
Source: Bank of England, Bank calculations.
Whether this matters for monetary control depends on the level of reserves at the point
digital currencies are introduced, and the type of monetary control regime being operated.
'floor' systems, with a level of
As of today, most major central banks use so-called
reserves (injected via QE) that far exceeds most estimates of aggregate demand from the
banking system. With such abundant reserves, even quite large unexpected variations in
reserves holdings need not threaten monetary control A'
('Zone in Chart 7).
That may change as central banks unwind their QE holdings.11 As the aggregate level of
reserves falls, the chances of a sudden reserves drain pushing up on market rates
('Zone B'
increase in Chart 7). Of course no-one knows with any certainty where this
inflection point lies. So central banks must either aim to stop asset unwind well before that
point is reached (the approach announced by the FOMC), or have tools in place ready to
allow banks to replace the reserves depleted by asset sales/redemptions as and when
they need to (the approach we expect to take in the UK).12
None of this fundamentally changes the nature of the challenges facing central banks in
maintaining monetary control. But it does underscore the importance of reflecting
operational needs in the design of potential future digital currency frameworks.13
5. Digital currencies may alter the size and composition of central bank assets
Most of my remarks today have focused on the potential implications of digital currencies
for central bank liabilities. But of course, for every liability, there also has to be an asset.
Whether those assets are, in total, any larger than today depends, in part, on whether new
digital currencies cause a net increase in demand for central bank liabilities, or simply
substitute for reserves or banknotes. A narrow digital currency that largely cannibalised
banknote demand, for example, might have little or no impact. By contrast, a broad digital
currency with many attractive payments features could materially increase the demand for
central bank liabilities.
The impact of any increase in demand on the size and composition of central bank assets
I've
depends on whether, and how, central banks choose to accommodate that demand.
already noted that, in systems like the UK's, digital currencies may cause some banks
whose deposit bases have been partially disintermediated to increase their borrowing from
market-wide facilities. A more interesting case could arise if the central bank chooses
instead to back persistently higher demand with more long-lasting assets, for example to
to today's banknote
reduce rollover risk. At modest size, that may look little different
programmes. But if digital currencies took off at scale, careful thought would be needed
as to how best to structure such asset holdings to manage balance sheet risks, and
minimise any unintentional interference with other policy uses of the balance sheet.14
Conclusion
CBDCs, if adopted, would be the first new type of central bank liability for centuries. They
could have important implications for the size, composition and risk profile of our balance
sheets; for the monetary policy transmission mechanism, and for monetary control. We
need to understand these effects, and build them into the design of CBDCs and our
operational toolkits. But, by themselves, balance sheet considerations do not obviously
present any 'redline' arguments
against CBDC adoption, if that is the chosen way forward.
Indeed, while the technologies for such currencies would be new, the use of the central
bank balance sheet to provide state-backed transactional money is one of our most
longstanding functions. The dog may be old, but it can still perform new tricks!
I am very grateful to Joshua Jones and India Rimmer for their assistance in preparing
these remarks; and to Andrew Bailey, Sarah Breeden, Shiv Chowla, Rohan Churm,
Jon Cunliffe, Rafael Kinston, Jeremy Leake, Amber McAlone, Ali Moussavi, Huw Pill,
Dave Ramsden, Francine Robb, Christina Segal-Knowles and Cormac Sullivan for their
advice and comments.