Banking and Financial Intermediation
Department of Applied Finance
2026-06-02
Course description:
Key approaches:
Before we walk through twelve weeks of material in one hour, here is the spine of the whole course:
Three big ideas
How to use this review
This deck does not replace the weekly lectures. It is a navigation map. For any concept you are unsure about, jump back to the weekly slides.
A financial system encompasses various financial intermediaries, markets, regulators, and infrastructure in the generation and distribution of financial resources.
Financial intermediation is part of the financial system.
A banking analogue of the Modigliani and Miller (1958) theorem would imply that banks are useless with perfect financial markets.
The existence of banks (and other financial intermediaries) must be justified by their roles in mitigating market frictions.
Bank failure has large negative externalities — depositor losses, credit-supply collapse, real-economy damage (cf. the GFC). Hence heavy regulation:
The two are complementary, not substitutes.
For every risk in this course we apply the I-M-M framework:
Why capital regulation exists
Bank failures impose costs on people who never agreed to bear them — depositors, borrowers, taxpayers. Capital is the first line of defence that keeps those costs internal to shareholders, not external to the public.
Capital absorbs losses and mitigates insolvency risk. The level a bank holds is guided by:
Note
Basel III is our focus, of course.
Under Basel III, depositary institutions (DIs) calculate and monitor four capital ratios:
Common equity Tier 1 (CET1) risk-based capital ratio \[ \text{CET1 capital ratio} = \frac{\text{CET1 capital}}{\text{Risk-weighted assets}} \tag{1}\]
Tier 1 risk-based capital ratio \[ \text{Tier 1 capital ratio} = \frac{\text{Tier 1 capital}}{\text{Risk-weighted assets}} \tag{2}\]
Total risk-based capital ratio \[ \text{Total capital ratio} = \frac{\text{Total capital}}{\text{Risk-weighted assets}} \tag{3}\]
Tier 1 leverage ratio \[ \text{Tier 1 leverage ratio} = \frac{\text{Tier 1 capital}}{\text{Total exposure}} \tag{4}\]
Important
\[\text{Tier 1} = \text{CET1} + \text{Additional Tier 1}, \quad \text{Total Capital} = \text{Tier 1} + \text{Tier 2}\]
Two approaches to measure credit RWA (since Basel II):
The minimum required capital ratios: \[ \begin{aligned} \text{CET1 capital ratio} &= \frac{\text{CET1 capital}}{\text{Risk-weighted assets}} \ge 4.5\% \\ \text{Tier 1 capital ratio} &= \frac{\text{Tier 1 capital}}{\text{Risk-weighted assets}} \ge 6\% \\ \text{Total capital ratio} &= \frac{\text{Total capital}}{\text{Risk-weighted assets}} \ge 8\% \\ \text{Tier 1 leverage ratio} &= \frac{\text{Tier 1 capital}}{\text{Total exposure}} \ge 4\% \end{aligned} \tag{5}\]
Basel III adds two buffers — both CET1 only — that sit above the minimums:
The point of the buffers is automatic restraint: as the buffer is eaten, dividend and bonus payouts are choked off before the bank hits the binding minimum.
So far, the capital ratios (specifically, RWA) are calculated to account for the DI’s credit risk. However, a DI’s insolvency risk can also manifest from interest rate risk, market risk, operational risk, and more.
In Basel III, RWA should be the sum of three components:
Important
The RWA in the minimum capital ratios (Equation 5) is the sum of all three RWAs.
We covered only the RWA for credit risk.
Interest Rate Risk
Interest rate risk is the possibility of a financial loss due to changes in interest rates.
Why interest rate risk matters — SVB, again
Silicon Valley Bank had bought long-dated Treasuries when rates were near zero. When the Fed raised rates aggressively in 2022–23, those bonds’ market value fell sharply — turning interest rate risk into a liquidity crisis the moment depositors demanded their money. Maturity mismatch is the oldest banking risk and still the most lethal.
One of the key functions performed by financial institutions (especially depositary institutions) is maturity transformation. For DIs, they take short-term deposits from depositors and make long-term loans to borrowers. As a result,
As discussed previously, the three pillars of Basel framework (since Basel II) include:
The Pillar 1 involves a capital adequacy framework surrounding minimum ratios of various capital (CET1, Tier 1, Total) to RWA.
The Interest Rate Risk in the Banking Book (IRRBB) is part of the Basel capital framework’s Pillar 2 (supervisory review) and Pillar 3 (disclosure).
The repricing (funding-gap) model is a book-value cash-flow analysis of the difference between interest income on assets and interest paid on liabilities over each maturity bucket. APRA requires smaller ADIs to use it for banking-book interest-rate exposure.
Repricing gap = \(RSA - RSL\), where RSA/RSL are rate-sensitive assets/liabilities that reprice within a given maturity bucket (e.g. variable-rate mortgages, term deposits).
\[ \Delta NII_i = GAP_i \times \Delta R_i = (RSA_i - RSL_i) \times \Delta R_i \]
where \(\Delta NII_i\) is the change in net interest income in bucket \(i\).
The essence of duration gap model is the concept of duration, which is covered in introductory finance courses.
Duration directly measures the interest rate sensitivity of an asset or liability:
\[ \frac{\Delta P}{P} = - D \times \frac{\Delta R}{1+R} = - MD \times \Delta R \tag{6}\]
where
The larger the numerical value of \(D\), the more sensitive is the price of that asset or liability to changes or shocks in interest rates.
Important
The relationship is only true for small changes in the yield.
Duration can be used to measure a financial institution’s duration gap to evaluate the FI’s overall interest rate exposure. It is possible to calculate the duration of the asset portfolio and of the liability portfolio.
Duration of assets portfolio:
\[ D_A = \sum_{i=1}^{N_A} w_{iA} \times D^A_i \]
where \(N_A\) is the total number of assets, \(w_{iA}\) is the market value weight of asset \(i\), \(D^A_i\) is the duration of asset \(i\).
So, change of assets value for a given change in interest rate is
\[ \Delta A = - D_A \times A \times \frac{\Delta R}{1+R} \tag{7}\]
Duration of liabilities portfolio:
\[ D_L = \sum_{i=1}^{N_L} w_{iL} \times D^L_i \]
where \(N_L\) is the total number of liabilities, \(w_{iL}\) is the market value weight of liability \(i\), \(D^L_i\) is the duration of liability \(i\).
So, change of liabilities for a given change in interest rate is
\[ \Delta L = - D_L \times L \times \frac{\Delta R}{1+R} \tag{8}\]
Since \(A = L + E\), we have \(\Delta E = \Delta A - \Delta L\). Substituting Equation 7 and Equation 8 and assuming the rate shock is the same on both sides:
\[ \Delta E = - (D_A - D_L k) \times A \times \frac{\Delta R}{1+R} \tag{9}\]
where \(k = L/A\) is leverage. The effect on net worth decomposes into three terms:
Market Risk
Market risk is uncertainty of an FI’s earnings on its trading portfolio caused by changes, particularly extreme changes, in market conditions such as the price of an asset, interest rates, market volatility, and market liquidity.
FIs are concerned about the potential impact of changing market conditions on their trading book and ultimately their net worth and solvency.
A natural question becomes:
How to quantify such impact? What is the potential change in value of trading portfolio for a given period?
More specifically,
Answering these questions leads to the development of two important concepts for measuring market risk exposure:
We start with the concept of Value at Risk (VaR), then discuss its limitations and the use of Expected Shortfall (ES).
Suppose we know the distribution of an asset’s returns over a specific period (in the future), then for a given confidence level \(c\in[0,1]\) (e.g., \(c=0.95\)), we can partition the distribution into two parts: one (in red) that represents a proportion of \((1-c)\) of the distribution and the other (in blue) accounting the remaining \(c\) proportion.
Therefore, the cutoff value of returns that separates the two parts defines:
Over the years, many models have been developed to compute VaR.
This is because we do not have the return distribution of trading portfolio over a specific period in the future.
Therefore, different assumptions lead to different models and approaches. We are interested in three in this course:
VaR’s drawbacks became evident in the GFC: returns plunged into the fat tail, and VaR projections badly underestimated actual losses. Regulators have since replaced VaR with expected shortfall (ES) — also called “conditional VaR” — the average loss beyond the VaR threshold.
\[ ES(c) = \frac{1}{1-c}\int_c^1 VaR(u)\,du \]
For \(c = 95\%\), ES is the area under the loss distribution from the 95th to the 100th percentile.
ES is the average of losses that occur beyond the VaR level. It provides a better risk assessment by considering the tail of the loss distribution.
In addition, an important advantage of ES over VaR is that ES is additive.
Potential issues with the use of ES include:
Why we spent two weeks on credit
For most banks, credit risk is by some distance the biggest single source of unexpected losses. The RWA table below makes the point: for every Australian major, RWA for credit risk is roughly 6–10x RWA for market or operational risk.
As suggested by Table 1 below, credit risk is likely the most significant risk factor, the risk that the promised cash flows from loans and securities may not be paid in full (e.g., borrower defaults).
| CBA | Westpac | NAB | ANZ | Macquarie | |
|---|---|---|---|---|---|
| RWA for credit risk | 362,869 | 339,758 | 355,554 | 349,041 | 97,485 |
| RWA for market risk | 61,968 | 51,676 | 38,274 | 41,967 | 11,663 |
| RWA for operational risk | 43,155 | 55,175 | 41,178 | 42,319 | 15,828 |
| Other RWA | 0 | 4,809 | 0 | 0 | 0 |
| Total RWA | 467,992 | 451,418 | 435,006 | 433,327 | 124,976 |
The return on assets approach adjusts for fees, compensating balances, and reserve requirements.
\[ 1+k = 1+\frac{f+(BR+\phi)}{1-b(1-RR)} \]
Because of default risk, the expected return differs from the promised return. With repayment probability \(p\):
\[ 1+E(r) = p(1+k) + (1-p)\cdot 0 \]
i.e. a probability-weighted average of full repayment (\(1+k\)) and zero recovery.1
Many different qualitative and quantitative models are employed to assess the default risk on loans and bonds.
Credit scoring models use observed borrower characteristics to
Scoring models might help to:
Three broad types
Risk-adjusted return on capital (RAROC) was pioneered by Bankers Trust (acquired by Deutsche bank in 1998).
\[ RAROC = \frac{\text{One-year net income on a loan}}{\text{Loan risk}} \] where \[ \text{One-year net income on loan} = (\text{Spread} + \text{Fees}) \times \text{Dollar value of the loan outstanding} \] and Loan risk can be measure by, for example, duration. \[ \frac{\Delta LN}{LN} = - D_{LN} \frac{\Delta R}{1+R} \] so that \[ \underbrace{\Delta LN}_{\text{dollar risk exposure}} = - \underbrace{D_{LN}}_{\text{duration of loan}} \times \underbrace{LN}_{\text{loan amount}} \times \underbrace{\frac{\Delta R}{1+R}}_{\text{shock}} \]
Rationale:
Note
The KMV Corporation1 turned this relatively simple idea into a credit monitoring model.
Many of the largest U.S. FIs are now using this model to determine the expected default frequency (EDF) of large corporations.
Two simple models widely employed to measure credit risk concentration in the loan portfolio:
MPT can be used to measure and control an FI’s aggregate credit risk exposure.
Any model that seeks to estimate an efficient frontier for loans needs to determine and measure three things:
The fundamental lesson of MPT is that by taking advantage of its size, an FI can diversify considerable amounts of credit risk as long as the returns on different assets are imperfectly correlated with respect to their default risk adjusted returns.
Moody’s RiskFrontier applies MPT to the loan portfolio using EDF (from Moody’s Credit Monitor) and LGD as primary inputs — no need for loan returns to be normally distributed.
Three inputs per borrower \(i\):
Fastest-growing types of swaps. Most important type of credit derivatives.
Why CDS?
We examine two types of credit swaps:
The textbook bank run, updated
The classic image of a bank run is a queue around the block. The 2023 image is a Slack channel. SVB lost a quarter of its deposit base in 24 hours. The deposit-runoff assumptions baked into the LCR were calibrated on pre-smartphone behaviour — regulators are now revisiting them.
Liquidity risk is a normal aspect of everyday management of a financial institution (FI). It can arise on both sides of the balance sheet:
Purchased liquidity — buy funds in the market.
Stored liquidity — liquidate assets.
Post-GFC, the BCBS introduced two new minimum liquidity standards: LCR (short-term, since Jan 2015) and NSFR (structural, since Jan 2018). Both apply to internationally active banks above size thresholds.
The LCR ensures a DI holds enough high-quality liquid assets (HQLA) to survive a 30-day stress scenario calibrated on GFC conditions:
\[ \text{LCR} = \frac{\text{Stock of HQLA}}{\text{Total net cash outflows over 30 days}} \ge 100\% \]
Reported monthly.
HQLA — assets that stay liquid in stress and are unencumbered. Split into:
Net cash outflows over 30 days:
\[\text{Net outflows} = Out - \min(In, 75\% \times Out)\]
Cash flows are computed by applying regulator-set draw-down factors to each asset/liability type.
NSFR targets structural funding stability over a one-year horizon — reducing reliance on short-term wholesale funding (a key GFC failure mode).
\[ \text{NSFR} = \frac{\text{Available stable funding (ASF)}}{\text{Required stable funding (RSF)}} \ge 100\% \]
Reported quarterly since 2018.
Abnormal deposit drains can trigger a bank run — fuelled by solvency concerns, contagion from related DIs, or sudden preference shifts. A systemic, contagious run is a bank panic.
The two main insulation devices:
Moral hazard, the dark side of safety nets
Both backstops are necessary — and both encourage risk-taking. Deposit insurance lets weak banks bid for deposits at the same rate as strong banks. A generous discount window lets banks economise on costly HQLA. The regulator’s job is to price the insurance and the access so the subsidy doesn’t outrun the public benefit.
Stored liquidity (asset-side) — historically dominant.
Purchased liquidity (liability-side) — dominant today.
The day-to-day game is risk-return trade-off: liquid assets earn less; under-shooting LCR/NSFR triggers charges; over-shooting ties up earning assets. Management of the RBA Exchange Settlement Account (ESA) is at the centre of this.1
The cash market is the overnight interbank market where banks lend/borrow ES balances.
Pre-COVID: the RBA managed ES supply via daily repurchase agreements (repos) to keep the cash rate near target.
Post-COVID: the RBA’s monetary operations changed substantially:
Aim: construct a low-cost and low-withdrawal-risk liability portfolio. The two are in tension — low-cost liabilities (demand deposits) have high withdrawal risk; low-withdrawal-risk liabilities (CDs) carry higher cost.
Deposit liabilities
Non-deposit liabilities
The risks that hit when you cross a border
An FI’s overall FX exposure in any given currency can be measured by the net position exposure, which is measured in local currency as
\[ \begin{aligned} \text{Net exposure}_i &= (\text{FX assets}_i - \text{FX liabilities}_i) + (\text{FX bought}_i - \text{FX sold}_i) \\ &=\text{Net foreign assets}_i + \text{Net FX bought}_i \end{aligned} \]
where \(i\) represents the \(i\)th currency.
Potential loss in any currency \(i\):
\[ \text{Dollar loss/gain}_i = \text{Net exposure}_i \times \text{Shock to FX rate}_i \]
Greater exposure × greater FX volatility ⇒ greater daily earnings at risk (DEAR).
FX volatility itself reflects shifts in the demand/supply of a currency, often driven by inflation and interest-rate differentials — which leads us to the two parity conditions: PPP (inflation) and IRP (interest rates).
Nominal interest rate \(R\) is basically the sum of inflation \(i\) and real interest rate \(r\):
For two countries, e.g., Australia (AU) and United States (US), we have:
\[ \begin{aligned} R_{AU} &= i_{AU} + r_{AU} \\ R_{US} &= i_{US} + r_{US} \end{aligned} \]
Assuming real interest rates are equal across countries: \(r_{AU}=r_{US}\), then
\[ R_{AU} - R_{US} = i_{AU} - i_{US} \]
That is, the (nominal) interest rate spread between Australia and the United States represents the difference in inflation rates between the two countries.
Important
When inflation rates and/or interest rates change, foreign exchange rates (without government control) should adjust to account for relative differences in the price levels (inflation) between the two countries.
Purchasing Power Parity (PPP) is one theory explaining how this adjustment takes place — built on the law of one price: identical goods should have one price across markets in equilibrium.
The PPP theorem states that the change in the exchange rate equals the inflation differential:
\[ i_{domestic} - i_{foreign} = \frac{\Delta S_{domestic/foreign}}{S_{domestic/foreign}} \]
Quick example
Spot \(S_{AUD/CNY} = 0.17\). Inflation: Australia 4%, China 10%. PPP gives: \[0.04 - 0.10 = \Delta S / 0.17 \Rightarrow \Delta S = -0.0102\] The yuan depreciates ~6% against the AUD; new rate ≈ 0.1598 AUD/CNY.
To illustrate (covered) interest rate parity (IRP), let’s consider two investment strategies.
Strategy 1: Domestic Investment
Strategy 2: Foreign Investment with Forward Contract
For these two strategies to have the same return (and eliminate arbitrage opportunities), the returns on both should be equivalent when the foreign investment is converted back using the forward rate. This gives us the CIRP condition:
\[ 1 + r_d = \frac{(1 + r_f) \cdot F}{S} \]
Rearranging, we can see the relation between interest rates and the forward rate:
\[ F = S \cdot \frac{1 + r_d}{1 + r_f} \]
On-balance-sheet hedging
Off-balance-sheet hedging
A sovereign country’s (negative) decisions on its debt obligations or the obligations of its public and private organizations may take two forms: repudiation and restructuring.
OBS items are contingent assets and liabilities — they shape the future balance sheet and produce positive or negative cash flows. True net worth = market value of on- plus off-balance-sheet activities.
Major types
Why banks use OBS
OBS is not just risk-increasing — much of it is hedging (interest-rate, FX) and so reduces insolvency risk. Big, creditworthy banks earn substantial OBS fee income.
For most of the 20th century, banking followed a simple model: originate-to-hold. A bank made a loan, kept it on its books, and collected interest until maturity.
Today, the dominant model is originate-to-distribute:
A model with consequences
The originate-to-distribute model fuelled the 2008 global financial crisis: once banks no longer held the loans they originated, their incentive to screen and monitor borrowers collapsed. Subprime mortgages were originated, securitised, sold, and the risk landed everywhere except on the originator’s balance sheet.
A market hiding in plain sight
The U.S. secondary loan trading market has grown to roughly US$800 billion in annual trading volume in recent years (LSTA). This market barely existed in 1990.
Traditional short-term loan sales
Leveraged loan sales
Note
The definition of “leveraged loan” is ambiguous: some use spreads (e.g. +125 bps), others use rating (BB- or lower).
Participation — the buyer is not a party to the original credit agreement. They take only partial control and bear double risk: borrower and selling FI.
Assignment — the more common form. All rights transfer; the buyer has a direct claim on the borrower.
Good bank / bad bank carve-outs are a special kind of loan sale.
Asset securitisation packages loans into newly created securities — asset-backed securities (ABS) — sold to investors. Two mechanisms, both creating off-balance-sheet subsidiaries:
The SIV problem — Citi, 2007
SIVs hold long-term assets funded with short-term paper — that is maturity transformation without deposit insurance. When ABCP markets froze in 2007, Citi’s seven SIVs (~US$58B) lost market access. Citi consolidated them back onto its balance sheet — the first signal that the GFC would be a bank-balance-sheet problem, not just an investor problem.
The MBB deposit-insurance subsidy
By pledging collateral to MBB holders, the FI reduces the assets backing insured depositors — effectively transferring risk to the deposit-insurance scheme. This is why APRA caps Australian covered-bond asset encumbrance at 8% of an ADI’s domestic assets.
Securitisation never went away after 2008; it migrated.
Was 2020 the next subprime?
In 2018 the Fed, BoE, IMF and BIS all flagged leveraged-loan CLOs as a systemic risk. COVID-19 was the stress test — CLOs survived, in part because of unprecedented central-bank intervention. Whether they would survive a normal recession is still an open question.
Traditional banks face pressure on every side:
Silicon Valley Bank, 10 March 2023
SVB lost US$42 billion of deposits in a single day — a quarter of its deposit base — after a Slack-and-Twitter-driven panic among its tech-VC clients. The FDIC took it over the next morning. This was the first social-media-driven bank run at systemic scale. Digital channels are not just a customer-experience story; they are a liquidity-risk story.
FinTech failure modes
| Bank | Notes |
|---|---|
| Up | Mobile-only, launched 2018; runs on Bendigo & Adelaide Bank’s ADI |
| UBank | NAB-owned; relaunched 2022 on the 86 400 tech stack after NAB acquired 86 400 in 2021 |
| Judo Bank | Full ADI granted April 2019; SME-focused; ASX-listed November 2021 |
| Alex Bank | Full ADI granted 22 December 2022 |
| ANZ Plus | ANZ’s in-house digital bank, launched 2022 on a new cloud core |
Important
To take deposits in Australia, you need an Authorised Deposit-taking Institution (ADI) licence from APRA. The Restricted ADI (RADI) pathway (since 2018) lowers the entry barrier — Volt, Xinja and Judo all used it.
The wave none of the textbooks anticipated. Since ChatGPT (Nov 2022), banks have moved from cautious pilots to scaled deployment.
New risks to manage
PSD2 (EU, 2018) was the first regulatory move to open banking. Australia’s equivalent is the Consumer Data Right:
A CBDC is a digital form of fiat currency issued by the central bank. Two flavours:
Why bank treasurers worry
If households can hold central-bank money directly — risk-free, instantly transferable — why hold uninsured commercial-bank deposits? The fear is a structural outflow of deposits to CBDC, forcing banks into more expensive wholesale funding and shrinking credit supply. Chiu et al. (2023) and Niepelt (2024) show the effect depends on design (interest-bearing? capped? how are reserves recycled?).
| Mechanism | Risk moves from… | …to |
|---|---|---|
| Capital regulation (Wk 3) | depositors | shareholders (equity buffers) |
| Hedging with derivatives (Wk 4/5) | the FI | the counterparty |
| Loan sales (Wk 11) | originating FI | the buyer (often a non-bank) |
| Securitisation (Wk 11) | originating FI | ABS/CLO investors |
| Open banking (Wk 12) | the incumbent bank | whoever the customer authorises |
| CBDC (Wk 12) | commercial-bank deposit base | the central bank’s balance sheet |
AFIN8003 Banking and Financial Intermediation