Securitisation: Key Concepts, Structures, Benefits, and Risks

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  • context: Securitisation creates new securities (ABS) whose income comes from a pool of assets that are not themselves securities (typically loans). It links a new security to the income stream of an underlying reference portfolio.

  • key definitions

    • Security: a tradable financial instrument in a secondary market (e.g., bonds, notes, commercial paper, shares). These are typically issued in large, identical lots enabling trading.

    • Loans and similar assets: can be sold bilaterally but are not securities because they lack a broad secondary-market tradability due to unique terms.

    • Asset-Backed Securities (ABS): the securitised instruments whose income comes from a reference portfolio of assets (the loans or other receivables).

    • SPV (Special Purpose Vehicle): a separate, insolvency-remote legal entity created to hold the reference portfolio and issue the ABS.

    • Reference portfolio (receivables): the pool of assets providing the income that supports the ABS.

  • why securitisation exists (two main purposes)

    • Create a tradable instrument for investors to access income from illiquid assets that they could not invest in directly.

    • Allow the originator (the lender) to transfer assets into the SPV, freeing up balance-sheet resources and reducing exposure to those assets (or matching assets to liabilities and obtaining liquidity).

  • general architecture

    • The originator ( Original lender or issuer) identifies a pool of assets and transfers them to the SPV (via the trust arrangement).

    • The SPV issues ABS to investors and uses the proceeds to purchase the reference portfolio from the originator.

    • The income from the reference portfolio (e.g., loan interest, lease payments, royalties) flows to the SPV, which pays the ABS coupons and principal according to a predefined waterfall.

    • The SPV remains the holder of the assets for the life of the ABS; the reference portfolio does not disappear, it is relocated to the SPV, and the ABS circulate in the secondary market.

  • terminology and scope

    • ABS is used as the umbrella term for securitised products; RMBS (Residential Mortgage-Backed Securities) and CMBS (Commercial Mortgage-Backed Securities) are subcategories.

    • In practice, the term ABS is often used broadly, though media sometimes refer specifically to RMBS/CMBS.

    • Example assets: auto loans, residential mortgages, leases (car leases), royalties (e.g., intangible property like music rights).

  • Australia-specific context (illustrative data as of March 2022)

    • The most common securitisation activity is residential mortgage loan securitisation in long-term bonds issued domestically.

    • Of the securitised assets, residential mortgage loans represented about $0.130 billion out of a total asset-backed securities pool of $0.162 billion AUD.

    • Long-term bonds issued domestically accounted for about $0.150 billion of the total $0.162 billion ABS on issue.

    • After the Global Financial Crisis (GFC), levels have recovered but did not reach 2007 peaks (around $0.270 billion AUD).

    • ABS on issue today involve assets issued by both ADIs (authorised deposit-taking institutions) and non-ADIs with relatively equal shares.

  • structure of the chapter (high-level)
    1) The process of securitisation
    2) The benefits of securitisation
    3) The dangers of securitisation

  • conceptual nuance about the asset transfer

    • When securitisation occurs, the original assets still exist; they are relocated to the SPV and become the collateral income source for the ABS.

    • The ABS are tradable in organised secondary markets, while the reference portfolio remains on the SPV balance sheet.

    • Common misperception: the reference portfolio and the ABS are the same instrument; in reality, they are two linked, but distinct, parts of the securitisation structure.

  • flow of funds (conceptual)

    • Investors purchase ABS from the SPV using funds that are then used by the SPV to purchase the reference portfolio from the originator.

    • Income from the reference portfolio is the source for the coupons paid to ABS investors. If the securitised assets generate, for example, loan interest, that income is used to pay ABS coupons.

    • In some cases, credit enhancements or servicing arrangements mean the originator continues to collect payments on behalf of the SPV in return for a servicing fee.

  • preparatory note about a technical nuance

    • In some sources, the reference portfolio is described as being divided into tranches; this is a misinterpretation. The SPV issues tranches of ABS, but the reference portfolio remains a single pool that backs the entire set of ABS; the line of credit and other instruments can complicate flows, but the reference portfolio itself is not divided into tranches.

  • illustrative cash-flow diagram references

    • Flow-of-funds diagrams illustrate how ABS are funded and how income from the reference portfolio flows to investors.

    • The diagrammatic representation helps explain how the SPV borrows to purchase the reference portfolio and how the income streams pay the ABS sequentially.

  • important note on simple vs. complex securitisations

    • Early securitisations issued homogeneous ABS with the same terms. Later, tranching introduced different risk/return profiles and seniority. A common three-tranche structure is:

    • Senior tranche: highest credit quality, lowest yield, paid first.

    • Mezzanine tranche: intermediate risk/return.

    • Junior (equity) tranche: highest risk, highest yield.

    • Some deals have many more tranches (e.g., a Firstmac RMBS deal in 2020 with seven tranches).

  • key formula: allocation of reference-portfolio income across tranches (waterfall)

    • Let I be the total income generated by the reference portfolio in a period.

    • Let CS, CM, C_J be the promised coupon payments for the senior, mezzanine, and junior tranches, respectively.

    • Allocation rules (per period):

    • AS = \min(I, CS)

    • AM = \min(\max(I - CS, 0), C_M)

    • AJ = \max(I - CS - C_M, 0)

    • If I is large enough to cover all promised coupons (I ≥ CS + CM + C_J), then each tranche receives its full coupon. If I is smaller, the waterfall prioritises payments to senior tranches first, then mezzanine, then junior.

  • credit enhancement concepts (internal vs external)

    • Internal mechanisms

    • Tranching itself as a form of credit enhancement (senior tranche typically rated higher than the reference-portfolio risk).

    • Over-collateralisation: the market value of the assets exceeds the face value of the ABS, creating a cushion to protect junior tranches.

    • Reserve funds: a pool of bank deposits or a cash reserve to cover shortfalls in coupon payments or principal recoveries.

    • External mechanisms

    • Mortgage insurance or guarantors to cover shortfalls when collateral values or income underperform.

    • In some markets (e.g., residential mortgage securitisation in Australia), mortgage insurance or guarantor arrangements can enable lower interest rates on ABS.

  • significance of the SPV structure

    • The SPV is insolvency-remote from the originator, with its own balance sheet, separate from the originator.

    • The SPV issues ABS on its liabilities side and holds the reference portfolio on its assets side.

    • The SPV’s existence allows the income from assets to be isolated from the originator’s credit and balance-sheet risks.

  • a note on governance and regulation

    • Credit-rating agencies (CRAs) assess risk and determine tranche sizes and ratings. The pricing and rating process has evolved due to historical mispricing risks.

    • The need for transparency and accountability in rating methodologies has increased; CRAs are increasingly required to separate rating activities from advisory activities to mitigate conflicts of interest.

  • practical implications and ethical considerations

    • Securitisation can improve liquidity and enable risk transfer, but it also creates incentives for adverse selection and moral hazard if originators do not retain any risk (skin in the game).

    • The 2007–2009 crisis highlighted the dangers of misaligned incentives, weak rating practices, and difficulties in tracing risk across multiple SPVs and securitisations.

    • Regulators have responded with requirements such as retention rules (originators holding a stake in securitisations) to promote responsible lending.

2 Benefits of Securitisation

  • 2.1 Benefits for the originator

    • Enable quick removal of a pool of loans from the balance sheet, freeing capital and liquidity.

    • SPV purchases assets automatically, reducing the need to find direct buyers for loans.

    • Transfer of credit risk from originator to ABS investors reduces balance-sheet risk for the originator.

    • For banks, securitisation can reduce risk-weighted assets (RWA): loans carry positive risk weights, while central-bank deposits carry zero weight; thus replacing loans with deposits can reduce RWA.

    • The ability to match-fund assets with liabilities, replacing uncertain interest income with servicing-based income, and enabling new lending can support ongoing lending activity.

    • Servicing fees earned by the originator provide ongoing income and can support equity growth; self-securitisation (originator buys its own ABS) can preserve optionality for future securitisations.

    • Some argue securitisation is cheaper funding than issuing new liabilities, with coupon rates reflecting the reference portfolio’s credit quality. Note: this argument presupposes a narrow focus on the SPV/originator separation; affordable comment: ABS does not count as a direct liability of the originator in all configurations.

  • 2.2 Benefits for ABS investors

    • Access to exposures to lending without needing a credit license to hold loans directly.

    • Ability to target specific loan sub-categories (e.g., residential mortgages, SME loans) rather than the entire lender portfolio.

    • Isolation from other activities of the originator due to SPV insolvency remoteness.

    • Ability to select risk/return profile via tranche choice (senior for lower risk, junior for higher yield).

    • ABS are tradable in organised secondary markets, enabling liquidity and exit options for investors (e.g., funds, insurers, superannuation funds, banks).

  • 2.3 Benefits for the financial system

    • Spreading credit risk across multiple investors reduces concentration risk on any single lender.

    • Potentially increases overall funding available for lending, subject to investor demand for ABS.

    • However, for banks, the dynamics may differ since loans can create deposits directly; securitisation is more impactful for non-bank originators.

3 Dangers of Securitisation

  • 3.1 Increased adverse selection and moral hazard

    • If originators are not bearing credit risk (originate-and-securitize), there is an incentive to underprice risk, extend many loans to higher-risk borrowers, and avoid monitoring borrowers, because servicing fees are independent of borrower performance.

    • This mispricing and lack of ongoing monitoring contributed to the subprime mortgage crisis; NINJA loans (no income, no job, no assets) and teaser-rate loans increased default risk when rates reset.

    • Regulatory responses included requirements for ‘skin in the game’—originators must retain some risk in the securitised assets to align incentives.

  • 3.2 Challenging rating of the tranches

    • The creation of multiple tranches complicates risk assessment; even AAA senior RMBS tranches have defaulted in some cases.

    • Conflicts of interest in rating agencies (rating for pay vs advisory work) have prompted reforms to separate roles and improve methodology transparency.

    • The distribution of risk across many investors can make it harder to identify affected parties in a default, especially when securitisations themselves are securitised in turn (i.e., ABS backed by ABS).

  • 3.3 The SPVs are not regulated like banks

    • SPVs typically do not face the same capital requirements as banks, which can concentrate risk in ways that are harder to monitor.

    • The lack of uniform regulatory treatment for SPVs has been a source of concern during financial stress periods.

4 Conclusion

  • Securitisation plays a useful role in the financial system by providing liquidity, risk transfer, and access to funding for a wide range of lenders (not only banks).

  • It also introduces potential dangers, including misaligned incentives, rating-risk mispricings, difficulties tracing risk across structures, and regulatory gaps for SPVs.

  • The Australian government has supported securitisation during crises (GFC and COVID-19) to maintain lending to SMEs, including measures such as government-backed ABS purchases and structured finance support funds (e.g., AOFM programs).

  • The balance between benefits and risks depends on design (tranches, credit enhancements), regulation (retention rules, transparency), and market demand for ABS.

5 Appendix: When the originator is a bank

  • Key configurations and money flows (illustrative summaries)

    • Case A: SPV and ABS investors have accounts in a bank other than the securitising bank

    • The sale of the loan pool injects central bank money into the SPV’s account via the bank of the SPV, reducing SPV balances.

    • Case B: SPV and ABS investors are customers of the securitising bank

    • Central bank money is not increased; bank deposits on the liability side of the securitising bank adjust instead of central bank money.

    • Case C: SPV is a customer of the bank but ABS investors are not

    • The sale reduces SPV deposits if SPV holds an account with the securitising bank; funds received from ABS investors move as central-bank money between banks.

    • Case D: Mixed configurations (some ABS investors are customers; some are not)

    • Money flows vary, but securitisation cannot be described as a guaranteed source of funds for the originator.

  • Servicing and bank equity effects vary by configuration; in some cases servicing raises bank equity, in others it affects deposits or central bank money differently.

  • Conclusion for banks: securitisation does not universally create new central-bank money; the impact on the bank’s balance sheet depends on the specific SPV/investor configuration and on how funds move between accounts. In most cases, securitisation cannot be described as a sure source of money for the originator.

6 References and notes

  • References include Australian Securitisation Journal, Clayton Utz, and related materials.

  • A note regarding accuracy of online sources: some resources (e.g., Investopedia) have misstatements about reference portfolios and tranches; the distinction between the reference portfolio (assets) and the ABS (securities) is important for proper understanding.

Equations and key numbers cited in the content above are representative from the material and illustrate the principles of securitisation, cash-flow waterfalls, and capitalization effects.