Restructuring Basel’s capital buffers

Douglas Elliott at Oliver Wyman has written a short post which I think makes a useful contribution to the question of whether the capital buffers in the BCBS framework are serving their intended purpose.

The short version is that he argues the Countercyclical Capital Buffer (CCyB) has worked well while the Capital Conservation Buffer (CCB) has not. The solution he proposes is that the “the Basel Committee should seriously consider shrinking the CCB and transferring the difference into a target level of the CCyB in normal times”. Exactly how much is up for debate but he uses an example where the base rate for the CCyB is 1.0% and the CCB is reduced by the same amount to maintain the status quo.

The idea of having a non-zero CCyB as the default setting is not new. The Bank of England released a policy statement in April 2016 that had a non zero CCyB at its centre (I wrote about that approach in this post from April 2018). What distinguishes Elliott’s proposal is that he argues that the increased CCyB should be seeded by a transfer from the CCB. While I agree with many of his criticisms of the CCB (mostly that it is simply not usable in practice), my own view is that a sizeable CCB offers a margin of safety that offers a useful second line of defence against the risk that a bank breaches its minimum capital requirement. My perspective is heavily influenced by a concern that both bankers and supervisors are prone to underestimate the extent to which they face an uncertain world.

For anyone interested, this post sets out my views on how the cyclical capital buffer framework should be constructed and calibrated. This issue is especially relevant for Australian banks because APRA has an unresolved discussion paper which includes a proposal to increase the size of the capital buffers the Australian banks are expected to maintain. I covered that discussion paper here. A speech that APRA Chair Wayne Byres gave in May 2020 covering some of the things APRA had learned from dealing with the economic fallout of COVID-19 is also worth checking out (covered in this post).

Tony – From the Outside

A BCBS review of the costs and benefits of higher bank capital requirements

The economic rational for higher bank capital requirements that have been implemented under Basel III is built to a large extent on an analytical model developed by the BCBS that was published in a study released in 2010. The BCBS has just (June 2019) released a paper by one of its working groups which reviews the original analysis in the light of subsequent studies into the optimal capital question. The 2019 Review concludes that the higher capital requirements recommended by the original study have been supported by these subsequent studies and, if anything, the optimal level of capital may be higher than that identified in the original analysis.

Consistent with the Basel Committee’s original assessment, this paper finds that the net macroeconomic benefits of capital requirements are positive over a wide range of capital levels. Under certain assumptions, the literature finds that the net benefits of higher capital requirements may have been understated in the original Committee assessment. Put differently, the range of estimates for the theoretically-optimal level of capital requirements … is likely either similar or higher than was originally estimated by the Basel Committee.

The costs and benefits of bank capital – a review of the literature; BCBS Working Paper (June 2019)

For anyone who is interested in really understanding this question as opposed to simply looking for evidence to support a preconceived bias or vested interest, it is worth digging a bit deeper into what the paper says. A good place to start is Table 1 from the 2019 Review (copied below) which compares the assumptions, estimates and conclusions of these studies:

Pay attention to the fine print

All of these studies share a common analytical model which measures Net benefits as a function of:

Reduced Crisis Probability x Crisis Cost – Output Drag (loan spreads).

So the extent of any net benefit depends on the extent to which:

  • More capital actually reduces the probability of a crisis and/or its economic impact,
  • The economic impact of a financial crisis is a permanent or temporary adjustment to the long term growth trajectory of the economy – a permanent effect supports the case for higher capital, and
  • The cost of bank debt declines in response to higher capital – in technical terms the extent of the Modigliani Miller (MM) offset, with a larger offset supporting the case for higher capital.

The authors of the 2019 Review also acknowledge that interpretation of the results of the studies is complicated by the fact that different studies use different measures of capital adequacy. Some of the studies provide optimal capital estimates in risk weighted ratios, others in leverage ratios. The authors of the 2019 Review have attempted to convert the leverage ratios to a risk weighted equivalent but that process will inevitably be an imperfect science. The definition of capital also differs (TCE, Tier 1 & CET1).

The authors acknowledge that full standardisation of capital ratios is very complex and lies beyond the scope of their review and nominate this as an area where further research would be beneficial. In the interim (and at the risk of stating the obvious) the results and conclusions of this 2019 Review and the individual studies it references should be used with care. The studies dating from 2017, for example, seem to support a higher value for the optimal capital range compared to the 2010 benchmark. The problem is that it is not clear how these higher nominal ratio results should be interpreted in the light of increases in capital deductions and average risk weights such as we have seen play out in Australia.

The remainder of this post will attempt to dig a bit deeper into some of the components of the net benefit model employed in these types of studies.

Stability benefits – reduced probability of a crisis

The original 2010 BCBS study concluded that increasing Tangible Common Equity from 7% to 10% would reduce the probability of a financial crisis by 1.6 percentage points.

The general principle is that a financial crisis is a special class of economic downturn in which the severity and duration is exacerbated by a collapse in confidence in the banking system due to widespread doubts about the solvency of one or more banks which results in a contraction in the supply of credit.

It follows that higher capital reduces the odds that any given level of loss can threaten the actual or perceived solvency of the banking system. So far so good, but I think it is helpful at this point to distinguish the core losses that flow from the underlying problem (e.g. poor credit origination or risk management) versus the added losses that arise when credit supply freezes in response to concerns about the solvency or liquidity of the banking system.

Higher capital (and liquidity) requirements can help to mitigate the risk of those second round losses but they do not in any way reduce the economic costs of the initial poor lending or risk management. The studies however seem to use the total losses experienced in historical financial crises to calculate the net benefit rather than specific output losses that can be attributed to credit shortages and any related drop in employment and/or the confidence of business and consumers. That poses the risk that the studies may be over estimating the potential benefits of higher capital.

This is not saying that higher capital requirements are a waste of time but the modelling of optimal capital requirements must still understand the limitations of what capital can and cannot change. There is, for example, evidence that macro prudential policy tools may be more effective tools for managing the risk of systemic failures of credit risk management as opposed to relying on the market discipline of equity investors being required to commit more “skin in the game“.

Cost of a banking crisis

The 2019 Review notes that

“recent refinements associated with identifying crises is promising. Such refinements have the potential to affect estimates of the short- and long-run costs of crises as well as our understanding of how pre-crisis financial conditions affect these costs. Moreover, the identification of crises is important for estimating the relationship between banking system capitalisation and the probability of a crisis, which is likely to depend on real drivers (eg changes in employment) as well as financial drivers (eg bank capital).

We considered above the possibility that there may be fundamental limitations on the extent to which capital alone can impact the probability, severity and duration of a financial crisis. The 2019 Review also acknowledges that there is an ongoing debate, far from settled, regarding the extent to which a financial crisis has a permanent or temporary effect on the long run growth trajectory of an economy. This seemingly technical point has a very significant impact on the point at which these studies conclude that the costs of higher capital outweigh the benefits.

The high range estimates of the optimal capital requirement in these studies typically assume that the impacts are permanent. This is big topic in itself but Michael Redell’s blog did a post that goes into this question in some detail and is worth reading.

Banking funding costs – the MM offset

The original BCBS study assumed zero offset (i.e. no decline in lending rates in response to deleveraging). This assumption increase the modelled impact of higher capital and, all other things equal, reduces the optimal capital level. The later studies noted in the BCBS 2019 Review have tended to assume higher levels of MM offset and the 2019 Review concludes that the “… assumption of a zero offset likely overstated the costs of higher capital nonbank loan rates”. For the time being the 2019 Review proposes that “a fair reading of the literature would suggest the middle of the 0 and 100% extremes” and calls for more research to “… help ground the Modigliani-Miller offset used in estimating optimal bank capital ratios”.

Employing a higher MM offset supports a higher optimal capital ratio but I am not convinced that even the 50% “split the difference” compromise is the right call. I am not disputing the general principle that risk and leverage are related. My concern is that the application of this general principle does not recognise the way in which some distinguishing features of bank balance sheets impact bank financing costs and the risk reward equations faced by different groups of bank stakeholders. I have done a few posts previously (here and here) that explore this question in more depth.

Bottom line – the BCBS itself is well aware of most of the issues with optimal capital studies discussed in this post – so be wary of anyone making definitive statements about what these studies tell us.

The above conclusion is however subject to a number of important considerations. First, estimates of optimal capital are sensitive to a number of assumptions and design choices. For example, the literature differs in judgments made about the permanence of crisis effects as well as assumptions about the efficacy of post crisis reforms – such as liquidity regulations and bank resolution regimes – in reducing the probability and costs of future banking crisis. In some cases, these judgements can offset the upward tendency in the range of optimal capital.

Second, differences in (net) benefit estimates can reflect different conditioning assumptions such as starting levels of capital or default thresholds (the capital ratio at which firms are assumed to fail) when estimating the impact of capital in reducing crisis probabilities.2

Finally, the estimates are based on capital ratios that are measured in different units. For example, some studies provide optimal capital estimates in risk-weighted ratios, others in leverage ratios. And, across the risk-weighted ratio estimates, the definition of capital and risk-weighted assets (RWAs) can also differ (eg tangible common equity (TCE) or Tier 1 or common equity tier 1 (CET1) capital; Basel II RWAs vs Basel III measures of RWAs). A full standardisation of the different estimates across studies to allow for all of these considerations is not possible on the basis of the information available and lies beyond the scope of this paper.

This paper also suggests a set of issues which warrant further monitoring and research. This includes the link between capital and the cost and probability of crises, accounting for the effects of liquidity regulations, resolution regimes and counter-cyclical capital buffers, and the impact of regulation on loan quantities.

The costs and benefits of bank capital – a review of the literature; BCBS Working Paper (June 2019)

Summing up

I would recommend this 2019 Literature Review to anyone interested in the question of how to determine the optimal capital requirements for banks. The topic is complex and important and also one where I am acutely aware that I may be missing something. I repeat the warning above about anyone (including me) making definitive statements based on these types of studies.

That said, the Review does appear to offer support for the steps the BCBS has taken thus far to increase capital and liquidity requirements. There are also elements of the paper that might be used to support the argument that bank capital requirements should be higher again. This is the area where I think the fine print offers a more nuanced perspective.

Tony

The Countercyclical Capital Buffer

This post uses a recent BCBS working paper as a stepping off point for a broader examination of how the countercyclical capital buffer (CCyB) can help make the banking system more resilient.

This post uses a recent BCBS working paper as a stepping off point for a broader examination of how the countercyclical capital buffer (CCyB) can help make the banking system more resilient. The BCBS paper is titled “Towards a sectoral application of the countercyclical capital buffer: A literature review – March 2018” (BCBS Review) and its stated aim is to draw relevant insights from the existing literature and use these to shed light on whether a sectoral application of the CCyB would be a useful extension of the existing Basel III framework under which the CCyB is applied at an aggregate country level credit measure. The views expressed in Working Papers like this one are those of their authors and do not represent the official views of the Basel Committee but they do still offer some useful insights into what prudential supervisors are thinking about.

Key points

  1. I very much agree with the observation in the BCBS Review that the standard form of the CCyB is a blunt instrument by virtue of being tied to an aggregate measure of credit growth
  2. And that a sectoral application of the CCyB (operating in conjunction with other sector focussed macro prudential tools) would be an improvement
  3. But the CCyB strategy that has been developed by the Bank of England looks to be a much better path to pursue
  4. Firstly, because it directly addresses the problem of failing to detect/predict when the CCyB should be deployed and secondly because I believe that it results in a much more “usable” capital buffer
  5. The CCyB would be 1% if APRA adopted the Bank of England strategy (the CCyB required by APRA is currently 0%) but adopting this strategy does not necessarily require Australian banks to hold more capital at this stage of the financial cycle
  6. One option would be to align one or more elements of APRA’s approach with the internationally harmonised measure of capital adequacy and to “reinvest” the increased capital in a 1% CCyB.

First a recap on the Countercyclical Capital Buffer (aka CCyB).

The CCyB became part of the international macro prudential toolkit in 2016 and is intended to ensure that, under adverse conditions, the banking sector in aggregate has sufficient surplus capital on hand required to maintain the flow of credit in the economy without compromising its compliance with prudential requirements.

A key feature in the original BCBS design specification is that the buffer is intended to be deployed in response to high levels of aggregate credit growth (i.e high relative to the sustainable long term trend rates) which their research has identified as an indicator of heightened systemic risk. That does not preclude bank supervisors from deploying the buffer at other times as they see fit, but responding to excess credit growth has been a core part of the rationale underpinning its development.

The BCBS Review

The BCBS Review notes that the CCyB works in theory but concedes there is, as yet, virtually no empirical evidence that it will work in practice. This is not surprising given that it has only been in place for a very short period of time but still important to remember. The BCBS Review also repeatedly emphasises the point that the CCyB may help to mitigate the credit cycle but that is a potential side benefit, not the main objective. Its primary objective is to ensure that banks have sufficient surplus capital to be able to continue lending during adverse economic conditions where losses will be consuming capital.

The Review argues that the CCyB is a useful addition to the supervisor’s tool kit but is a blunt instrument that impacts all sectors of the economy indiscriminately rather than just targeting the sectors which are the source of systemic concern. It concludes that applying the CCyB at a sectoral level might be more effective for three reasons

  • more direct impact on the area of concern,
  • stronger signalling power, and
  • smaller effects on the wider economy than the Basel III CCyB.

The Review also discusses the potential to combine a sectoral CCyB with other macro prudential instruments; in particular the capacity for the two approaches to complement each other;

Quote “Generally, macroprudential instruments that operate through different channels are likely to complement each other. The literature reviewed indicates that a sectoral CCyB could indeed be a useful complement to alternative sectoral macroprudential measures, including borrower-based measures such as LTV, LTI and D(S)TI limits. To the extent that a sectoral CCyB is more effective in increasing banks’ resilience and borrower-based measures are more successful in leaning against the sectoral credit cycle, both objectives could be attained more effectively and efficiently by combining the two types of instruments. Furthermore, there is some evidence that suggests that a sectoral CCyB could have important signalling effects and may therefore act as a substitute for borrower-based measures.”

A Sectoral CCyB makes sense

Notwithstanding repeated emphasis that the main point of the CCyB is to ensure banks can and will continue to support credit growth under adverse conditions, the Review notes that there is not much, if any, hard empirical evidence on how effective a release of the CCyB might be in achieving this. The policy instrument’s place in the macro prudential tool kit seems to depend on the intuition that it should help, backed by some modelling that demonstrates how it would work and a pinch of hope. The details of the modelling are not covered in the Review but I am guessing it adopts a “homo economicus” approach in which the agents act rationally. The relatively thin conceptual foundations underpinning the BCBS version of the CCyB are worth keeping in mind.

The idea of applying the CCyB at a sectoral level seems to make sense. The more targeted approach advocated in the Review should in theory allow regulators to respond to sectoral areas of concern more quickly and precisely than would be the case when the activation trigger is tied to aggregate credit growth. That said, I think the narrow focus of the Review (i.e. should we substitute a sectoral CCyB for the current approach) means that it misses the broader question of how the CCyB might be improved. One alternative approach that I believe has a lot of promise is the CCyB strategy adopted by the Bank of England’s Financial Policy Committee (FPC).

The Bank of England Approach to the CCyB (is better)

The FPC published a policy statement in April 2016 explaining that its approach to setting the countercyclical capital buffer is based on five core principles. Many of these are pretty much the same as the standard BCBS policy rationale discussed above but the distinguishing feature is that it “… intends to set the CCyB above zero before the level of risk becomes elevated. In particular, it expects to set a CCyB in the region of 1% when risks are judged to be neither subdued nor elevated.”

This contrasts with the generic CCyB, as originally designed by the BCBS, which sets the default position of the buffer at 0% and only increases it in response to evidence that aggregate credit growth is excessive. This might seem like a small point but I think it is a material improvement on the BCBS’s original concept for two reasons.

Firstly, it directly addresses the problem of failing to detect/predict when systemic risk in the banking system requires prudential intervention. A lot of progress has been made in dealing with this challenge, not the least of which has been to dispense with the idea that central banks had tamed the business cycle. The financial system however retains its capacity to surprise even its most expert and informed observers so I believe it is better to have the foundations of a usable countercyclical capital buffer in place as soon as possible after the post crisis repair phase is concluded rather than trying to predict when it might be required.

The FPC still monitors a range of core indicators for the CCyB grouped into three categories.

  • The first category includes measures of ‘non-bank balance sheet stretch’, capturing leverage in the broader economy and in the private non-financial (ie household and corporate) sector specifically.
  • The second category includes measures of ‘conditions and terms in markets’, which capture borrowing terms on new lending and investor risk appetite more broadly.
  • The third category includes measures of ‘bank balance sheet stretch’, which capture leverage and maturity/liquidity transformation in the banking system.

However the FPC implicitly accepts that it can’t predict the future so it substitutes a simple, pragmatic and error resilient strategy (put the default CCyB buffer in place ASAP) for the harder problem of trying to predict when it will be needed. This strategy retains the option of increasing the CCyB, is simpler to administer and less prone to error than the BCBS approach. The FPC might still miss the turning point but it has a head start on the problem if it does.

The FPC also integrates its CCyB strategy with its approach to stress testing. Each year the stress tests include a scenario:

“intended to assess the risks to the banking system emanating from the financial cycle – the “annual cyclical scenario”

The severity of this scenario will increase as risks build and decrease after those risks crystallise or abate. The scenario might therefore be most severe during a period of exuberance — for example, when credit and asset prices are growing rapidly and risk premia are compressed. That might well be the point when markets and financial institutions consider risks to be lowest. And severity will be lower when exuberance has corrected — often the time at which markets assess risks to be largest. In leaning against these tendencies, the stress-testing framework will lean against the cyclicality of risk taking: it will be countercyclical.”

The Bank of England’s approach to stress testing the UK banking system – October 2015 (page 5)

The second reason  I favour the FPC strategy is because I believe it is likely to result in a more “usable” buffer once risk crystallizes (not just systemic risk) and losses start to escalate. I must admit I have struggled to clearly articulate why this would be so but I think the answer lies partly in the way that the FPC links the CCyB to a four stage model that can be interpreted as a stylised description of the business cycle. The attraction for me in the FPC’s four stage model is that it offers a coherent narrative that helps all the stakeholders understand what is happening, why it is happening, what will happen next and when it will happen.

The BCBS Review talks about the importance of communication and the FPC strategy offers a good model of how the communication strategy can be anchored to a coherent and intuitive narrative that reflects the essentially cyclical nature of the banking industry. The four stages are summarised below together with some extracts setting out the FPC rationale.

Stage 1: The post-crisis repair phase in which risks are subdued – the FPC would expect to set a CCyB rate of 0%

FPC rationale: “Risks facing the financial system will normally be subdued in a post-crisis repair and recovery phase when the financial system and borrowers are repairing balance sheets. As such, balance sheets are not overextended. Asset and property prices tend to be low relative to assessed equilibrium levels. Credit supply is generally tight and the risk appetite of borrowers and lenders tends to be low. The probability of banks coming under renewed stress is lower than average.”

Stage 2: Risks in the financial system re-emerge but are not elevated – the FPC intends to set a positive CCyB rate in the region of 1% after the economy moves into this phase.

FPC rationale: ‘In this risk environment, borrowers will not tend to be unusually extended or fragile, asset prices are unlikely to show consistent signs of over, or under, valuation, and measures of risk appetite are likely to be in line with historical averages”. As such, it could be argued that no buffer is required but the FPC view is that a pre-emptive strategy is more “robust to the inherent uncertainty associated with measuring risks to financial stability”. It also allows subsequent adjustments to be more graduated than would be possible if the CCyB was zero.

Stage 3: Risks in the financial system become elevated: stressed conditions become more likely – the FPC would expect to increase the CCyB rate beyond the region of 1%. There is no upper bound on the rate that can be set by the FPC.

FPC rationale: “As risks in the financial system become elevated, borrowers are likely to be stretching their ability to repay loans, underwriting standards will generally be lax, and asset prices and risk appetite tend to be high. Often risks are assumed by investors to be low at the very point they are actually high. The distribution of risks to banks’ capital at this stage of the financial cycle might have a ‘fatter tail’ [and] stressed outcomes are more likely.”

Stage 4: Risks in the financial system crystallise – the FPC may cut the CCyB rate, including where appropriate to 0%.

FPC rationale: “Reducing the CCyB rate pre-emptively before losses have crystallised may reduce banks’ perceived need to hoard capital and restrict lending, with consequent negative impacts for the real economy. And if losses have crystallised, reducing the CCyB allows banks to recognise those losses without having to restrict lending to meet capital requirements. This will help to ensure that capital accumulated when risks were building up can be used, thus enhancing the ability of the banking system to continue to support the economy in times of stress.”

The March 2018 meeting of the FPC advised that the CCyB applying to UK exposures would remain unchanged at the 1% default level reflecting its judgement that the UK banking system was operating under Stage 2 conditions.

Calibrating the size of the CCyB

The FPC’s approach to calibrating the size of the CCyB also offers some interesting insights. The FPC’s initial (April 2016) policy statement explained that a “CCyB rate in the region of 1%, combined with other elements of the capital framework, provides UK banks with sufficient capital to withstand a severe stress. Given current balance sheets, the FPC judges that, at this level of the CCyB, banks would have sufficient loss-absorbing capacity to weather a macroeconomic downturn of greater magnitude than those observed on average in post-war recessions in the United Kingdom — although such estimates are inherently uncertain.”

The first point to note is that the FPC has chosen to anchor their 1% default setting to a severity greater than the typical post war UK recession but not necessarily a GFC style event. There is a school of thought that maintains that more capital is always better but the FPC seems to be charting a different course. This is a subtle area in bank capital management but I like the the FPC’s implied defence of subtlety.

What is sometimes lost in the quest for a failure proof banking system is a recognition of the potential for unintended consequence. All other things being equal, more capital makes a bank less at risk of insolvency but all other things are almost never equal in the real world. Banks come under pressure to find ways to offset the ROE dilution associated with more capital. I know that theory says that a bank’s cost of equity should decline as a result of holding more capital so there is no need to offset the dilution but I disagree (see this post for the first in a proposed series where I have started to set out my reasons why). Attempts to offset ROE dilution also have a tendency to result in banks taking more risk in ways that are not immediately obvious. Supervisors can of course intervene to stop this happening but their already difficult job is made harder when banks come under pressure to lift returns. This is not to challenge the “unquestionably strong” benchmark adopted by APRA but simply to note that more is not always better.

Another problem with just adding more capital is that the capital has to be usable in the sense that the capital ratio needs to be able to decline as capital is consumed by elevated losses without the bank coming under pressure to immediately restore the level of capital it is expected to hold. The FPC strategy of setting out how it expects capital ratios to increase or decrease depending on the state of the financial cycle helps create an environment in which this can happen.

Mapping the BOE approach to Australia

APRA has set the CCyB at 0% whereas the BOE approach would suggest a value of at least 1% and possibly more given that APRA has felt the need to step in to cool the market down. It is important to note that transitioning to a FPC style CCyB does not necessarily require that Australian banks need to hold more capital. One option would be to harmonise one or more elements of APRA’s approach to capital measurement (thereby increasing the reported capital ratio) and to “reinvest” the surplus capital in a CCyB. The overall quantum of capital required to be unquestionably strong would not change but the form of the capital would be more usable to the extent that it could temporarily decline and banks had more time to rebuild  the buffer during the recovery phase.

Summing up

A capital adequacy framework that includes a CCyB that is varied in a semi predictable manner over the course of the financial cycle would be far more resilient than the one we currently have that offers less flexibility and is more exposed to the risk of being too late or missing the escalation of systemic risk all together.

Tell me what I am missing …