Mortgage risk weights fact check revisited – again

The somewhat arcane topic of mortgage risk weights is back in the news. It gets popular attention to the extent they impact the ability of small banks subject to standardised risk weights to compete with bigger banks which are endorsed to use the more risk sensitive version based on the Internal Ratings Based (IRB) approach. APRA released a Discussion Paper (DP) in February 2018 titled “Revisions to the capital framework for authorised deposit-taking institutions”. There are reports that APRA is close to finalising these revisions and that this will address the competitive disadvantage that small banks suffer under the current regulation.

This sounds like a pretty simple good news story – a victory for borrowers and the smaller banks – and my response to the discussion paper when it was released was that there was a lot to like in what APRA proposed to do. I suspect however that it is a bit more complicated than the story you read in the press.

The difference in capital requirements is overstated

Let’s start with the claimed extent of the competitive disadvantage under current rules. The ACCC’s Final Report on its “Residential Mortgage Price Inquiry” described the challenge with APRA’s current regulatory capital requirements as follows:

“For otherwise identical ADIs, the advantage of a 25% average risk weight (APRA’s minimum for IRB banks) compared to the 39% average risk weight of standardised ADIs is a reduction of approximately 0.14 percentage points in the cost of funding the loan portfolio. This difference translates into an annual funding cost advantage of almost $750 on a residential mortgage of $500 000, or about $15 000 over the 30 year life of a residential mortgage (assuming an average interest rate of 7% over that period).”

You could be forgiven for concluding that this differential (small banks apparently required to hold 56% more capital for the same risk) is outrageous and unfair.

Just comparing risk weights is less than half the story

I am very much in favour of a level playing field and, as stated above, I am mostly in favour of the changes to mortgage risk weights APRA outlined in its discussion paper but I also like fact based debates.

While the risk weights for big banks are certainly lower on average than those required of small banks, the difference in capital requirements is not as large as the comparison of risk weights suggests. To understand why the simple comparison of risk weights is misleading, it will be helpful to start with a quick primer on bank capital requirements.

The topic can be hugely complex but, reduced to its essence, there are three elements that drive the amount of capital a bank holds:

  1. The risk weights applied to its assets
  2. The target capital ratio applied to those risk weighted assets
  3. Any capital deductions required when calculating the capital ratio

I have looked at this question a couple of times (most recently here) and identified a number of problems with the story that the higher risk weights applied to residential mortgages originated by small bank places them at a severe competitive disadvantage:

Target capital ratios – The target capital adequacy ratios applied to their higher standardised risk weighted assets are in some cases lower than the IRB banks and higher in others (i.e. risk weights alone do not determine how much capital a bank is required to hold).

Portfolio risk – The risk of a mortgage depends on the portfolio not the individual loan. The statement that a loan is the same risk irrespective of whether it is written by a big bank or small bank sounds intuitively logical but is not correct. The risk of a loan can only be understood when it is considered as part of the portfolio the bank holds. All other things being equal, small banks will typically be less diversified and hence riskier than a big bank.

Capital deductions – You also have to include capital deductions and the big banks are required to hold capital for a capital deduction linked to the difference between their loan loss provisions and a regulatory capital value called “Regulatory Expected Loss”. The exact amount varies from bank to bank but I believe it increases the effective capital requirement by 10-12% (i.e. an effective RW closer to 28% for the IRB banks).

IRRBB capital requirement – IRB banks must hold capital for Interest Rate Risk in the Banking Book (IRRBB) while the small standardised banks do not face an explicit requirement for this risk. I don’t have sufficient data to assess how significant this is, but intuitively I would expect that the capital that the major banks are required to hold for IRRBB will further narrow the effective difference between the risk weights applied to residential mortgages.

How much does reducing the risk weight differential impact competition in the residential mortgage market?

None of the above is meant to suggest that the small banks operating under the standardised approach don’t have a case for getting a lower risk weight for their higher quality lower risk loans. If the news reports are right then it seems that this is being addressed and that the gap will be narrower. However, it is important to remember that:

  • The capital requirement that the IRB banks are required to maintain is materially higher than a simplistic application of the 25% average risk weight (i.e. the IRB bank advantage is not as large as it is claimed to be).
  • The standardised risk weight does not seem to be the binding constraint so reducing it may not help the small banks much if the market looks through the change in regulatory risk measurement and concludes that nothing has changed in substance.

One way to change the portfolio quality status quo is for small banks to increase their share of low LVR loans with a 20% RW. Residential mortgages do not, for the most part, get originated at LVR of sub 50% but there is an opportunity for small banks to try to refinance seasoned loans where the dynamic LVR has declined. This brings us to the argument that IRB banks are taking the “cream” of the high quality low risk lending opportunities.

The “cream skimming” argument

A report commissioned by COBA argued that:

“While average risk weights for the major banks initially rose following the imposition of average risk weight on IRB banks by APRA, two of the major banks have since dramatically reduced their risk weights on residential mortgages with the lowest risk of default. The average risk weights on such loans is now currently on average less than 6 per cent across the major banks.”

“Despite the imposition of an average risk weight on residential home loans, it appears some of the major banks have decided to engage in cream skimming by targeting home loans with the lowest risk of default. Cream skimming occurs when the competitive pressure focuses on the high-demand customers (the cream) and not on low- demand ones (the skimmed milk) (Laffont & Tirole, 1990, p. 1042). Cream skimming has adverse consequences as it skews the level of risk in house lending away from the major banks and towards other ADIs who have to deal with an adversely selected and far riskier group of home loan applicants.”

“Reconciling Prudential Regulation with Competition” prepared by Pegasus Economics May 2019 (page 43)

It is entirely possible that I am missing something here but, from a pure capital requirement perspective, it is not clear that IRB banks have a material advantage in writing these low risk loans relative to the small bank competition. The overall IRB portfolio must still meet the 25% risk weight floor so any loans with 6% risk weights must be offset by risk weights (and hence riskier loans) that are materially higher than the 25% average requirement. I suspect that the focus on higher quality low risk borrowers by the IRB banks was more a response to the constraints on capacity to lend than something that was driven by the low risk weights themselves.

Under the proposed revised requirements, small banks in fact will probably have the advantage in writing sub 50% LVR loans given that they can do this at a 20% risk weight without the 25% floor on their average risk weights and without the additional capital requirements the IRB banks face.

I recognise there are not many loans originated at this LVR band but there is an opportunity in refinancing seasoned loans where the combined impact of principal reduction and increased property value reduces the LVR. In practice the capacity of small banks to do this profitably will be constrained by their relative expense and funding cost disadvantage. That looks to me to be a bigger issue impacting the ability of small banks to compete but that lies outside the domain of regulatory capital requirements.

Maybe this potential arbitrage does not matter in practice but APRA could quite reasonably impose a similar minimum average RW on Standardised Banks if the level playing field argument works both ways. This should be at least 25% but arguably higher once you factor in the fact that the small banks do not face the other capital requirements that IRB banks do. Even if APRA did not do this, I would expect the market to start looking more closely at the target CET1 for any small bank that accumulated a material share of these lower risk weight loans.

Implications

Nothing in this post is meant to suggest that increasing the risk sensitivity of the standardised risk weights is a bad idea. It seems doubtful however that this change alone will see small banks aggressively under cutting large bank competition. It is possible that small bank shareholders may benefit from improved returns on equity but even that depends on the extent to which the wholesale markets do not simply look through the change and require smaller banks to maintain the status quo capital commitment to residential mortgage lending.

What am I missing …

Mortgage risk weights – fact check

It is frequently asserted that the major Australian banks have been “gifted” a substantially lower mortgage risk weight than the smaller banks. To be precise, the assertion is that the major banks are only required to hold capital based on a 25% risk weight versus 39% for smaller banks.

If you are not familiar with the arcane detail of bank capital adequacy, then you could be forgiven for concluding that this differential (small banks apparently required to hold 56% more capital for the same risk) is outrageous and unfair. While the risk weights for big banks are certainly lower on average than those required of small banks, I believe the difference in capital requirements is not as large as the simple comparison of risk weights suggests.

Bank capital requirements involve more than risk weights

To understand why this comparison of risk weights is misleading, it will be helpful to start with a quick primer on bank capital requirements. The topic can be hugely complex but, reduced to its essence, there are three elements that drive the amount of capital a bank holds:

  1. The risk weights applied to its assets
  2. The target capital ratio applied to those risk weighted assets
  3. Any capital deductions required when calculating the capital ratio

Problem 1 – Capital adequacy ratios differ

The comparison of capital requirements based on risk weights implicitly assumes that the regulator applies the same capital ratio requirement to all banks, but this is not the case. Big banks are targeting CET1 ratios based on the 10.5% Unquestionably Strong benchmark set by APRA while there is a greater range of practice amongst the smaller banks. Bendigo and Suncorp appear to be targeting a CET1 ratio in the range of 8.5 to 9.0% while the smaller of the small banks appear to be targeting CET1 ratios materially higher (say 15% or more).

If we confine the comparison to the alleged disadvantage suffered by Bendigo and Suncorp, then the higher risk weights they are required to apply to residential mortgages is substantially offset by the lower CET1 target ratios that they target (the 56% difference in capital required shrinks to something in the order of 30% if you adjust for the difference in target CET1 ratios).

Broadening the comparison to the smaller banks gets even more interesting. At face value the much higher CET1 ratios they appear to target suggest that they are doubly penalised in the required capital comparison but you have to ask why are they targeting such high CET1 ratios. One possible explanation is that the small less diversified mortgage exposures are in fact more risky than the more diversified exposures maintained by their larger competitors.

Problem 2 – You have to include capital deductions

This is quite technical I recognise but, in addition to the capital tied to the risk weight, the big banks are also required to hold capital for a capital deduction linked to the difference between their loan loss provisions and a regulatory capital value called “Regulatory Expected Loss”. This capital deduction increases the effective risk weight. The exact amount varies from bank to bank but I believe it increases the effective capital requirement by 10-12% (I.e. an effective RW closer to 28%). My understanding is that small banks are not required to make the same capital deduction.

Problem 3 – The Standardised risk weights for residential mortgages seem set to change

A complete discussion of the RW difference should also take account of the fact that APRA has proposed to introduce lower RW Categories for the smaller banks such their average RW may be lower than 39% in the future. I don’t know what the average RW for small banks would be under these new RW but that is a question you could put to the banks who use the 39% figure without acknowledging this fact.

Problem 4 – The risk of a mortgage depends on the portfolio not the individual loan

The statement that a loan is the same risk irrespective of whether it is written by a big bank or small bank sounds intuitively logical but is not correct. The risk of a loan can only be understood when it is considered as part of the portfolio the bank holds. Small banks will typically be less diversified than a big bank.

Problem 5 – What about the capital required for Interest Rate Risk in the Banking Book (IRRBB)?

I don’t have sufficient data to assess how significant this is, but intuitively I would expect that the capital that the major banks are required to hold for IRRBB will further narrow the effective difference between the risk weights applied to residential mortgages.

Summing up

My aim in this post was not to defend the big banks but rather to try to contribute some of the knowledge I have acquired working in this area to what I think is an important but misunderstood question. In the interests of full disclosure, I have worked for one of the large Australian banks and may continue to do work for them in the future.

On a pure risk basis, it seems to me that the loan portfolio of a large bank will tend to be more diversified, and hence lower risk, than that of a smaller bank. It is not a “gift” for risk weights to reflect this.

There is a legitimate debate to be had regarding whether small banks should be given (gifted?) an advantage that helps them compete against the big banks. That debate however should start with a proper understanding of the facts about how much advantage the large banks really have and the extent to which their lower risk weights reflect lower risk.

If you disagree tell me what I am missing …

“Between Debt and the Devil: Money, Credit and Fixing Global Finance” by Adair Turner (2015)

This book is worth reading, if only because it challenges a number of preconceptions that bankers may have about the value of what they do. The book also benefits from the fact that author was the head of the UK Financial Services Authority during the GFC and thus had a unique inside perspective from which to observe what was wrong with the system. Since leaving the FSA, Turner has reflected deeply on the relationship between money, credit and the real economy and argues that, notwithstanding the scale of change flowing from Basel III, more fundamental change is required to avoid a repeat of the cycle of financial crises.

Overview of the book’s main arguments and conclusions

Turner’s core argument is that increasing financial intensity, represented by credit growing faster than nominal GDP, is a recipe for recurring bouts of financial instability.

Turner builds his argument by first considering the conventional wisdom guiding much of bank prudential regulation prior to GFC, which he summarises as follows:

  • Increasing financial activity, innovation and “financial deepening” were beneficial forces to be encouraged
  • More compete and liquid markets were believed to ensure more efficient allocation of capital thereby fostering higher productivity
  • Financial innovations made it easier to provide credit to households and companies thereby enabling more rapid economic growth
  • More sophisticated risk measurement and control meanwhile ensured that the increased complexity of the financial system was not achieved at the expense of stability
  • New systems of originating and distributing credit, rather than holding it on bank balance sheets, were believed to disperse risks into the hands of those best placed to price and manage it

Some elements of Turner’s account of why this conventional wisdom was wrong do not add much to previous analysis of the GFC. He notes, for example, the conflation of the concepts of risk and uncertainty that weakened the risk measurement models the system relied on and concludes that risk based capital requirements should be foregone in favour of a very high leverage ratio requirement. However, in contrast to other commentators who attribute much of the blame to the moral failings of bankers, Turner argues that this is a distraction. While problems with the way that bankers are paid need to be addressed, Turner argues that the fundamental problem is that:

  • modern financial systems left to themselves inevitably create debt in excessive quantities,
  • in particular, the system tends to create debt that does not fund new capital investment but rather the purchase of already existing assets, above all real estate.

Turner argues that the expansion of debt funding the purchase or trading of existing assets drives financial booms and busts, while the debt overhang left over by the boom explains why financial recovery from a financial crisis is typically anaemic and protracted. Much of this analysis seems to be similar to ideas developed by Hyman Minsky while the slow pace of recovery in the aftermath of the GFC reflects a theme that Reinhart and Rogoff have observed in their book titled “This time is different” which analyses financial crises over many centuries.

The answer, Turner argues, is to build a less credit intensive growth model. In pursuing this goal, Turner argues that we also need to understand and respond to the implications of three underlying drivers of increasing credit intensity;

  1. the increasing importance of real estate in modern economies,
  2. increasing inequality, and
  3. global current account imbalances.

Turner covers a lot of ground, and I do not necessarily agree with everything in his book, but I do believe his analysis of what is wrong with the system is worth reading.

Let me start with an argument I do not find compelling; i.e. that risk based capital requirements are unreliable because they are based on a fundamental misunderstanding of the difference between risk (which can be measured) and uncertainty (which cannot):

  • Distinguishing between risk and uncertainty is clearly a fundamental part of understanding risk and Turner is not alone in emphasising its importance
  • I believe that means that we should treat risk based capital requirements with a healthy degree of scepticism and a clear sense of their limitations but that does not render them entirely unreliable especially when we are using them to understand relative differences in risk and to calibrate capital buffers
  • The obvious problem with non-risk based capital requirements is that they create incentives for banks to take higher risk that may eventually offset the supposed increase in soundness attached to the higher capital
  • It may be that Turner discounts this concern because he envisages a lower credit growth/intensity economy delivering less overall systemic risk or because he envisages a more active role for the public sector in what kinds of assets banks lend against; i.e. his support for higher capital may stem mostly from the fact that this reduces the capacity of private banks to generate credit growth

While advocating much higher capital, Turner does seem to part company with M&M purists by expressing doubt that equity investors will be willing to accept deleveraged returns. His reasoning is that returns to equity investments need a certain threshold return to be “equity like” while massively deleveraged ROE still contains downside risks that are unacceptable to debt investors.

Turning to the arguments which I think raise very valid concerns and deserve serious attention.

Notwithstanding my skepticism regarding a leverage ratio as the solution, the arguments he makes about the dangers of excessive credit growth resonate very strongly with what I learned during my banking career. Turner is particularly focussed on the downsides of applying excessive debt to the financing of existing assets, real estate in particular. The argument seems to be similar to (if not based on) the work of Hyman Minsky.

Turner’s description of the amount of money that banks can create as being “infinitely elastic” seems an overstatement to me (especially in the Australian context with the Net Stable Funding Ratio (NSFR) weighing on the capacity to grow the balance sheet) but the general point he is making about the way that credit fuelled demand for a relatively inelastic supply of desirable residential property tends to result in inflated property values with no real social value rings true.

What banks can do about this remains an open question given that resolving the problem with inelastic supply of property is outside their direct control but it is obviously important to understand the dynamics of the market underpinning their largest asset class and it may help them engage more constructively with public policy debates that seek to address the problem.

Turner’s analysis of the downsides of easy monetary policy (the standard response to economic instability) also rings true. He identifies the fact that lower interest rates tend to result in inflated asset values (residential property in particular given its perceived value as a safe asset) which do not address the fundamental problem of over-indebtedness and may serve to increase economic inequality. His discussion of the impact of monetary policy and easy credit on economic inequality is also interesting. The banks providing the credit in the easy money environment may not necessarily be taking undue risk and prudential supervisors have tools to ensure sound lending standards are maintained if they do believe there is a problem with asset quality. What may happen however is that the wealthier segments of society benefit the most under easy money because they have the surplus cash flow to buy property at inflated values while first homebuyers become squeezed out of the market. Again their capacity to address the problem may be limited but Turner’s analysis prompted me to reflect on what increasing economic inequality might mean for bank business models.

In addition to much higher bank capital requirements, Turner’s specific recommendations for moving towards a less credit intensive economy include:

  • Government policies related to urban development and the taxation of real estate
  • Changing tax regimes to reduce the current bias in favour of debt over equity financing (note that Australia is one of the few countries with a dividend imputation system that does reduce the bias to debt over equity)
  • Broader macro prudential powers for central banks, including the power to impose much larger countercyclical capital requirements
  • Tough constraints on the ability of the shadow banking system to create credit and money equivalents
  • Using public policy to produce different allocations of capital than would result from purely market based decisions; in particular, deliberately leaning against the market signal based bias towards real estate and instead favouring other “potentially more socially valuable forms of credit allocation”
  • Recognising that the traditional easy monetary policy response to an economic downturn (or ultra-easy in the case of a financial crisis such as the GFC) is better than doing nothing but comes at a cost of reigniting the growth in private credit that generated the initial problem, creating incentives for risky financial engineering and exacerbating economic inequality via inflating asset prices.

For those who want to dig deeper, I have gone into a bit more detail here on what Turner has to say about the following topics:

  • The way in which inefficient and irrational markets leave the financial system prone to booms and busts
  • The dangers of debt contracts sets out how certain features of these contracts increase the risk of instability and hamper the recovery
  • Too much of the wrong sort of debt describes features of the real estate market that make it different from other asset classes
  • Liberalisation, innovation and the credit cycle on steroids recaps on the philosophy that drove the deregulation of financial markets and what Turner believes to be the fundamental flaws with that approach. In particular his conclusion that the amount of credit created and its allocation is “… too important to be left to bankers…”
  • Private credit and money creation offers an outline of how bank deposits evolved to play an increasing role (the key point being that it was a process of evolution rather than overt public policy design choices)
  • Credit financed speculation discusses the ways in which credit in modern economies tends to be used to finance the purchase of existing assets, in particular real estate, and the issues that flow from this.
  • Inequality, credit and more inequality sets out some ways in which the extension of credit can contribute to increasing economic inequality
  • Capital requirements sets out why Turner believes capital requirements should be significantly increased and why capital requirements (i.e. risk weights) for some asset classes (e.g. real estate) should be be calibrated to reflect the social risk of the activity and not just private risks captured by bank risk models
  • Turner defence against the argument that his proposals are anti-markets and anti-growth.

APRA’s proposed revisions to capital requirements for residential mortgages

… there is a lot to like in what APRA have proposed but also some issues that would benefit from further thought

Many readers will be aware that APRA released a Discussion Paper (DP) last week titled “Revisions to the capital framework for authorised deposit-taking institutions”.   The paper sets out APRA’s proposed changes to ADI capital requirements defined by the Internal Ratings Based Approach (IRB) and Standardised Approach to Credit Risk, Interest Rate Risk in the Banking Book (IRRBB) and Operational Risk. The focus of this post will be the proposals impacting credit risk capital requirements for residential mortgage lending. This post presupposes that the reader is familiar with the detail of what APRA has proposed. For those of you who have not yet got around to reading the whole paper I have added a short summary of the proposals below (see “APRA’s proposals – in more detail”).

My gut reaction is that there is a lot to like in what APRA have proposed but there are also issues that deserve further consideration in order to address the risk of unintended consequence and to better deliver on the objectives of consistency, transparency and competitive neutrality.

Proposals which make sense to me:

  • The increased risk sensitivity of the proposed standardised RWs for residential mortgages is, I believe, a material enhancement of the capital adequacy framework
  • There are arguments (and indeed evidence) for why investor property loans can be as low risk as owner occupier loans (most of the  time) but APRA’s desire to address the systemic tail risk of this form of lending is I think an understandable policy objective for a prudential regulator to pursue
  • Continuing to pursue higher IRB RW via changes to the correlation factor also looks to be a better approach than the 20% floor on LGD currently applied and thankfully also up for revision
  • Applying a higher correlation factor to low PD loans also makes intuitive sense, especially if your primary concern is the systemic risk associated with the residential mortgage lending that dominates the balance sheets of your banking system
  • In addition, the potential for the correlation adjustment to reduce the sensitivity of residential mortgage RWA to the economic cycle (and hence reduce the risk of pro-cyclical stress on capital ratios) is particularly welcome though I believe there is much more to do on this general issue
  • The support for Lender’s Mortgage Insurance (LMI) is also welcome

Areas where I believe the proposed revised capital framework could be improved (or at least benefit from some more thought):

  • The discussion of relative standardised and IRB RW does not address the fact IRB banks are required to hold additional capital to cover any shortfall between loan loss provisions and Regulatory Expected Loss (REL)
  • Residential mortgage portfolios subject to the standardised approach should be subject to a minimum average RW in the same way that IRB portfolios are currently constrained by the 25% floor
  • Applying a fixed scalar to Credit RWA can be problematic as the composition of the loan portfolio continues to evolve

The discussion of comparative IRB and Standardised RW you typically encounter seems to assume that the two approaches are identical in every aspect bar the RW but people working at the coal face know that the nominal RW advantage the IRB banks have has been partly offset by a higher exposure measure the RW are applied to. It appears that APRA’s proposed revisions will partly address this inconsistency by requiring banks using the Standardised Approach to apply a 100% Credit Conversion Factor (CCF) to undrawn loan limits.  IRB banks are also required to take a Common Equity Tier 1 deductions for the shortfall between their loan loss provisions and REL. The proposed revisions do nothing to address this area of inconsistency and in fact the Discussion Paper does not even acknowledge the issue.

Residential mortgage portfolios subject to the standardised approach should be subject to a minimum average RW in the same way that IRB portfolios are constrained. The majority of new residential mortgages are originated at relatively high LVR (most at 70% plus and a significant share at 80% plus), but the average LVR will be much lower as principal is repaid (and even more so if you allow for the appreciation of property values).  The introduction of a 20% RW bucket for standardised banks poses the question whether these banks will have an advantage in targeting the refinancing of seasoned loans with low LVR’s. The IRB banks would seek to retain these customers but they will still be constrained by the 25% average RW mandated by the FSI while the standardised banks face no comparable constraint.

This is unlikely to be an issue in the short term but one of the enduring lessons learned during my time “on the inside” is that banks (not just the big ones) are very good at identifying arbitrages and responding to incentives. It is widely recognised that housing loans have become the largest asset on Australian bank balance sheets (The Royal Commission issued a background paper that cited 42% of assets as at September 2017) but the share was significantly less when I started in banking. There has been a collection of complex drivers at play here (a topic for another post) but the relatively low RW has not harmed the growth of this kind of lending. Consequently, it is dangerous to assume that the status quo will persist if incentives exist to drive a different outcome.

This competitive imbalance could be addressed quite simply if the standardised banks were also subject to a requirement that their average RW was also no lower than 25% (or some alternative floor ratio that adjusted for the differences in exposure and REL noted above).

Another lesson learned “on the inside” is that fixed scalars look simple but are often not. They work fine when the portfolio of assets they are scaling up is stable but will gradually generate a different outcome to what was intended as the composition of the loan book evolves over time. I don’t have an easy solution to this problem but, if you must use them, it helps to recognise the potential for unintended consequence at the start.

Read on below if you have not read the Discussion Paper or want more detail on the revisions APRA has proposed and how these changes are proposed to be reconciled with the FSI recommendation. This is my first real post so feedback would be much appreciated.

Above all, tell me what I am missing … 

Tony

Note: The original version of this post published 22 February 2018 stated that inconsistent measurement of the exposures at default between the standardised and IRB approaches  was not addressed by APRA’s proposed revisions. I believe now that the proposed application of a 100% CCF in the Standardised Approach would in fact address one of the areas of inconsistency. The treatment of Regulatory Expected Loss remains an issue however. The post was revised on 24 February to clarify these points.

APRA’s proposals – in more detail

Good quality loans fully secured by mortgages on occupied residential property (either rented or occupied by the borrower) have been assigned concessionary risk weights (RW) ever since risk weighted capital adequacy ratios were introduced under Basel I (1988). The most concessionary risk weight was initially set at 50% and reduced to 35% in the Basel II Standardised Approach (2006).

APRA currently applies the concessionary 35% RW to standard eligible mortgages with Loan Valuation Ratios (LVR) of 80% or better (or up to 90% LVR if covered by Lender’s Mortgage Insurance) while the best case scenario for a non-standard mortgage is a 50% RW. Progressively higher RW (50/75/100) are applied for higher risk residential mortgages.

Under the Standardised Approach, APRA proposes:

  • The classification of a Standard Eligible Mortgage will distinguish between lowest risk “Owner-occupied P&I” and a higher risk “Other residential mortgages” category which is intended to be conceptually similar to the “material dependence” concept employed by Basel III to distinguish loans where repayment depends materially on the cash flows generated by the property securing the loan
  • 6 RW bands for each of these two types of residential mortgage (compared to 5 bands currently)
  • Standard Eligible Mortgages with lower LVR loans to be assigned lower RW but these loans must also meet defined serviceability, marketability and valuation criteria to qualify for the concessionary RW
  • The higher RW applied to “Other residential mortgages” may take the form of a fixed risk-weight schedule (per the indicative RW in Table 3 of the Discussion Paper) but might also be implemented via a multiplier, applied to the RW for owner-occupied P&I loans, which might vary over time “… depending on prevailing prudential or financial stability objectives or concerns”
  • Relatively lower capital requirements to continue to apply where loans are covered by LMI but its preferred approach is to apply a RW loading to loans with LVR in excess of 80% that are not insured (i.e. the indicative RW in Table 3 assume that LMI covers the high LVR loans)
  • Non-Standard residential mortgages should no longer benefit from any RW concession and be assigned a flat 100% RW irrespective of LVR and LMI

While the IRB requirements impacting residential mortgages are largely unchanged under Basel III, APRA proposes the following changes to the Australian IRB Approach to reflect local requirements and conditions:

  • Increased capital requirements for investment and interest-only exposures; to be implemented via a higher correlation factor for these loans
  • The (currently fixed) correlation factor applied to residential mortgages to be amended to depend on probability of default (PD); reflecting empirical evidence that “… the default risk of lower PD exposures is more dependent on the economic cycle  and can consequently increase at a relatively higher rate in a downturn”
  • A reduction in the minimum Loss Given Default (LGD) from 20% to 10% (subject to APRA approval of the LGD model); in order to facilitate “… better alignment of LGD estimates to key drivers of loss such as LVR and LMI”
  • Capital requirements for non-standard mortgages use the standardised approach; increasing consistency between the IRB an standardised approaches

APRA’s proposals seek to strike a balance between risk sensitivity and simplicity but must also take account of the FSI recommendations that ADI capital levels be unquestionably strong while also narrowing the difference between standardised and IRB RWs for residential mortgages. APRA is undertaking a Quantitative Impact Study (QIS) to better understand the impact of its proposals but the DP flagged that APRA does not expect the changes to correlation factors to meet its objectives for increased capital for residential mortgage exposures.

APRA could just further ramp up the correlation factor to generate the target IRB RW (which I assume continues to be 25%) but the DP notes that this would create undesirable inconsistencies with the correlation factors applied to other asset classes. Consequently, the DP indicates that the target increase in IRB RWA will likely be pursued via

  • A fixed multiplier (scalar) applied to total Credit RWA (i.e. althoughBasel III removes the 1.06 Credit RWA scalar, APRA is considering retaining a scalar with a value yet to be determined); and
  • If necessary, by applying additional specific RWA scalars for residential (and commercial) property.

These scalars will be subject to consultation with the industry and APRA has committed to review the 10.5% CET1 benchmark for unquestionably strong capital should the net result of the proposed revisions result in an overall increase in RWA’s relative to current methodologies.