
ECL models cannot always capture emerging risks quickly enough, which is why management adjustments or overlays can be necessary in exceptional or transitional circumstances. An overlay should address a demonstrable gap between model output and the entity's reasonable, supportable view of expected credit losses; it should not become a permanent balancing figure. The strongest accounting files make the reasoning visible, so that a reviewer can understand not only the conclusion but also why plausible alternatives were rejected. Poorly governed overlays can double count risk, obscure model weakness and undermine comparability between reporting periods. A robust approach connects commercial substance, the Ind AS 109 decision criteria, measurement evidence and presentation consequences in one coherent file.
Start with a clearly identified model gap
The core requirement. An overlay should respond to a risk, data limitation or non-linearity that is not adequately reflected in the existing model or scenarios. In a controlled close process, management should describe the affected portfolio, causal mechanism, expected duration and why ordinary model inputs cannot capture the risk in time. A common weakness is using an overlay merely because the reported allowance appears too low or too high. The accounting result should reconcile to the underlying contract, valuation or subledger rather than rely on a standalone spreadsheet conclusion.
Choose a measurement basis linked to the risk
The principle. The amount should have a rational connection to the incremental expected loss being addressed rather than being a round percentage added to the total allowance. For a review-ready file, methods may use stressed migration, sector deterioration, targeted PD or LGD adjustments, expert scenarios or other evidence-based techniques. The risk to avoid is applying a portfolio-wide factor to exposures not affected by the identified risk. The working paper should identify the relevant facts, source data, judgement and conclusion so that an independent reviewer can reproduce the decision.
Prevent double counting
The technical anchor. The overlay should be assessed against macro scenarios, staging triggers, model calibrations and other post-model adjustments to confirm the same risk is not already captured. In application, a risk-to-model mapping can show where the issue enters the ECL framework and what residual gap remains. A frequent failure mode is retaining an old overlay after the underlying model has been recalibrated to capture the same effect. Where the conclusion is sensitive to a contractual clause or estimate, the file should show the alternative outcome and why the selected treatment is more appropriate.
Set an exit strategy
The accounting logic. Temporary adjustments should have explicit review triggers, sunset criteria and ownership so that they are removed, recalibrated or incorporated into the model when appropriate. Operationally, each reporting cycle should reassess whether the underlying risk persists and whether new data allow a more direct modelling response. The main judgement risk is allowing overlays to accumulate across periods without challenge. A concise review note should state the trigger, the rule applied, the evidence considered and the financial-statement consequence.
Govern overlays at the right level
The decision point. Material overlays should receive cross-functional review from credit risk, modelling, finance and senior governance bodies with clear challenge and approval. For implementation, papers should distinguish model output, overlay amount, rationale, sensitivity and final allowance by portfolio. Where errors often arise is treating a material post-model adjustment as an undocumented spreadsheet entry controlled by one person. Evidence should be retained at the same level of detail as the accounting conclusion, with assumptions version-controlled and exceptions explicitly approved.
Practical illustration
Suppose a portfolio is exposed to a newly announced sector restriction that is not present in historical data and is not yet captured in the macro model. Management may estimate an incremental loss effect for the affected segment using borrower-level or scenario evidence. The overlay should be targeted, independently reviewed and removed or absorbed into the model when the risk is better represented. The illustration is deliberately simplified: its purpose is to show how the accounting conclusion follows the underlying facts rather than to prescribe a single mechanical answer for every entity. Before posting an entry, the preparer should reconcile contractual terms, management's commercial intent, relevant estimates and system data to the specific accounting requirement. Where the outcome is sensitive, the file should show the key judgement and explain why the selected assumption is reasonable at the reporting date.
Documentation and control points
Professional application depends as much on process quality as technical knowledge. For this topic, a minimum control set should cover model-gap statement; quantification methodology; double-counting assessment; approval and challenge; and sunset and back-testing. Ownership should be clear between the business, finance and any legal, tax, valuation, credit-risk or other specialists whose evidence is required. Source data should be dated and version-controlled; manual adjustments should show preparer, reviewer, rationale and approval. The final accounting memorandum should connect the conclusion to the general ledger or relevant subledger, presentation and disclosures. If facts or estimates change, the entity should reassess the conclusion when required and preserve an audit trail explaining the change.
Closing perspective
A well-governed overlay is a transparent bridge between model limitations and expected-loss reality, not a substitute for model improvement. The most useful way to apply Ind AS 109 is to treat the requirement as a decision framework rather than a compliance slogan. When the facts, accounting criteria, measurement evidence, controls and disclosure implications are considered together, the result is more consistent across reporting periods and easier to explain to management, auditors and users of the financial statements.
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Explore related courses →References
- Ind AS 109, Financial Instruments — ICAI Compendium of Indian Accounting Standards 2025-2026
- Ind AS 107, Financial Instruments: Disclosures — ICAI Compendium of Indian Accounting Standards 2025-2026
