Chapter 29: Risk measurement and reporting Flashcards
(37 cards)
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features of a risk that would make it appropriate to model stochastically as opposed to deterministically
- has a high score (high frequence or severity) and there is a high prioristy to assess carefully
- has a high variability of possible outcomes
- has a lot of experience data on which to base probability distributions
- relates to financial guarantees or options
- involves a mismatching of assets and liabilities
‘single event’ insurance
one where there can only be a maximum of one claim
ways to allow for operational risk within an organisation
- a broad brush approach that does not perform any detailed analysis
- scenario analysis
why would we go for scenario analysis instead of stochastic modelling?
- risks might not be suitable for mathematical modelling
- Distribution would need so many subjective parameters so that value of using it would be eroded.
Steps in scenario analysis
- Grouping risks into broad categories - all risks involving fraud, all risks involving systsems - input from management may be needed
- development of a plausible adverse scenario - so that it is possible to quatify the impact of the risk, the scenario must be representative of all risks in that group.
- calculations of the consequences of the risk event occuring for each scenario - include redress paid to those affected, fines correcting systems and records and opportunity costs
- total costs calculated are taken as the financial cost of all the risks represented by the chosen scenario
What is the limitation to scenario testing ?
it can only quantify the severity of a scenario and not the probability
The limitation to scenario testing is that it can only quantify the severity of a scenario and not the probability
What are some of the ways to go around this limitation
- The organistation may use their capital model to determine the probability of an equivalent scenairio occuring
- they may have an idea of the probability of the scenario occuring and use this in conjuction to the severity to help caliberate or validate the capital model
stress scenario test
scenario testing + stress testing
two types of scenario stress test
- to identify the “weak areas” in the portfolio and investigate the effects of localised stress situations by looking at the effect of different combinations of correlations and volatilities
- to gauge the impact of maor market turmoil affecting all model parameters, while ensuring consistency between correlations while they are “stressed”
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reverse stress testing
- construction of a stress scenario that just allows the firm to be able to continue to meet its business plan
- identifying a scenario which would just be enough to stop the company fulfilling its strategic plan
Stochastic modelling as an extension of stress testing
- full stochastic model with all the variables that give rise to risk being incorporated as probability distributions
- and a full set of dynamic interactions between the variables specified
- the model can then determine the capital necessary to just avoid ruin at any probability level
ways to limit the complexity of a stochatic model
- restrict the duration (or time horizon) of the model
- limit the number of variables modelled stochastically and use a deterministic approach for the other variables - variables that only have an adverse effect when they move in one direction can be modelled stochastically e.g mortality and longevity
- carry out a number of runs with different single stochastic variable and then a single deterministc run using all the worst case scenarios together
limitations to stochastic modelling
- difficult to specify and build
- the run times of multiple variables become impractical
Explain why the effect of multiple risks may be less than the sum of individual risks
- Impact of diversification or less than perfect (even negative) correlation
- less than perfect correlation means that they are unlikely to occur at the same time
Different ways of aggregating risk
- stochastic modelling
- simple formulae if risk events are fully dependent
- correlation matrices
- copulas
Propose some likely correlations between risks
- Inflation risk is heavily corealted with expense risk for most long-term financial products
- Traditionaly, equity markets have moved in opposite directions to interest rates but in recent years, the correlation has not been so obvious
- Falling equity markets are likely to be corelated with increasing lapse rates on unit-linked savings products
- operational risk is likely to be weakly correlated with all other risks, because if management are concentrating on some other issue they may not be concentrating on routine operational matters
- In life insurance, the longevity risk on an annuity book is strongly negatively correlated with mortality risk on a term assurance book
Limiting property of correlation matrices
They assume that correlations do not vary under different conditions
Copula
a function which takes as inputs marginal cumulative distributiion functions and outputs a joint distribution function
Why is modelling tail risk particularly important for a financial service provider ?
Capital requirments are typically assessed in relation to events that would fall in the tails of distributiions
Deterministic approaches to measuring risk
- notional approach
- the factor sensitivity approach
- scenario sensitivity approach
stochastic approaches to measuring risk
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- deviation - standard deviation and tracking error
- Value at Risk
- probability of ruin
- Tail Value at Risk
Different ways to calculate VaR and tVar
- emperical
- parametric
- stochastic approach
- scenario analysis
Notional approach to measuring risk
- A notional approach to measuring risk involves a simplified or conceptual method that doesn’t require detailed quantitative data - hence a broad-brush risk measure
- It can be useful when you lack precise data but still want to gain a general understanding of the risk landscape
Notes do not give a precise definition so I used ChatGPT
Advantage to the notional approach to measuring risk
- simple to implement and interpret across the diverse range of organisations