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Reverse Stress Testing

Reverse Stress Testing. Ron Papanek. Agenda. What is Reverse Stress Testing? Why is it important? Practitioner Examples Single-Factor Multi-Factor Historical Monte Carlo Related Stress Tests Historical Unwind Liquidity Hedging. Reverse Stress Testing – What is it?. Definitions.

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Reverse Stress Testing

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  1. Reverse Stress Testing Ron Papanek

  2. Agenda • What is Reverse Stress Testing? • Why is it important? • Practitioner Examples • Single-Factor • Multi-Factor • Historical • Monte Carlo • Related Stress Tests • Historical Unwind • Liquidity • Hedging

  3. Reverse Stress Testing – What is it? Definitions • Portfolio Specific • Incorporating information specific to the fund company, or portfolio. • Create an Explanatory Narrative • Traditional Stress tests quantify loss from a real or potential event • Reverse Stress tests tell a story from the numbers. Traditional Stress Test Reverse Stress Test Shock  P&LP&L Shocks

  4. Reverse Stress Testing – Why is it Important? Engages Management The methodology leads to a better understanding of firm risk through the process of identifying thresholds and the exploration of macro scenarios Connects the portfolio risk to the business risk Provides a different perspective than traditional stress tests Provides a more thorough examination of tail risk Can yield more efficient hedging strategies Tells a story Advocated by Regulators FSA, BIS, FED, CRMPG have all voiced support for reverse stress testing “The emphasis of a ‘reverse-stress test’ would be on identifying the high impact stress events which would cause the firm to fail and considering the appropriate action, if any, to protect against such failure.” FSA 12/2008 (2.27) Identify systemic risk and trigger points for contagion

  5. Reverse Stress Testing Reverse Stress Test Methodologies Sensitivity Analysis • One Factor - Simple, Predictive, Multiple correlated factors • Multifactor – two or more independent risk factors Scenario Analysis • Historical – Date Range • Monte Carlo – Loss simulations

  6. Reverse Stress Testing - One Factor Traditional stress test • is a function • not necessarily monotonic. Reverse stress test • is not a function • Different shocks can produce the same P&L

  7. Two Factor Reverse Stress Test One Equity Shift P&L

  8. Sensitivity Analysis Multi-Factor • One Factor – One Dimension • Two Factors – Two Dimensions • Locking two factors together allows us to introduce a third factor

  9. Two Factor Reverse Stress Test One

  10. Multi-Factor Sensitivity Grid 20 % 3 0 % 40 % 50 %

  11. Reverse Stress Testing - Historical Steps • Run a traditional Historical stress test and sort by threshold violation. • Run same Historical stress test, but widen period from days to rolling periods, widening periods until loss threshold is triggered. • The output of the Reverse Historical Stress Test is a series of dates and date ranges.

  12. Reverse Stress Testing Weekly Historical Monthly Daily Daily Daily Daily 2 Day 2Day

  13. Reverse Historical Stress Test Match date scenario with events to explains the portfolio loss Single Date Date Range September 20, 2008 March 2003

  14. Reverse Stress Testing – Scenario Generation Monte Carlo How do we simulate a 100 year flood? • Run 100 years worth of Monte Carlo simulated returns • Run Monte Carlo simulated returns using correlation periods from different market regimes.

  15. Reverse Stress Testing - Scenario Historical / Monte Carlo Hybrid • Run long term Historical Simulation • Sort sims by loss threshold and use dates to create a period for correlation calculation • Run Monte Carlo simulated returns report using new “extreme correlation period” • Sort sims by loss threshold and aggregate risk factor scenarios

  16. Reverse Stress Testing - Simulations Historical / Monte Carlo Hybrid Historical Monte Carlo

  17. Monte Carlo Visualization Worst to Best

  18. Reverse Stress Testing - Simulation Monte Carlo by Position

  19. Reverse Stress Testing - Simulation

  20. Reverse Stress Testing - Simulation Monte Carlo Visualization • Visualization allows the inspection of hundreds or thousands of scenarios • Observe the distribution of individual scenarios (not just the average) • Visually identify hedge positions and hedge effectiveness

  21. Agenda • What is Reverse Stress Testing? • Why is it important? • Practitioner Examples • Single-Factor • Multi-Factor • Historical • Monte Carlo • Related Tools • Historical Unwind • Liquidity • Hedging

  22. Reverse Stress Testing – Related Tools Historical Unwind Benefits • Provides insight into Bubbles • Historical Stress Test Historical Unwind • Replays History Replays History in Reverse • Separates buy and hold from arbitrage strategies • Identifies increasing leverage • Can highlight trend following • Separates idiosyncratic trends within an asset class

  23. Reverse Stress Testing Historical Unwind 1 2 3 4 month month month month

  24. Reverse Stress Testing Historical Unwind

  25. Reverse Stress Testing Liquidity • Portfolio specific Risk • Risk - based on position not security • Test liquidation assumptions with acquisition history • Compare Lock-up to liquidity horizon

  26. Agenda • What is Reverse Stress Testing? • Why is it important? • Practitioner Examples • Single-Factor • Multi-Factor • Historical • Monte Carlo • Related Tools • Historical Unwind • Liquidity • Hedging

  27. Reverse Stress Testing - Hedging Hedge the Business not the Portfolio • Focus on hedging the tail • Identify and aggregate the most commonly occurring risk factor scenarios • Finding the cheapest and most efficient hedge • Strategies • Costless Collar • Correlated Asset Put Spread • Macro Scenario overlay

  28. Reverse Stress Testing - Conclusions • Engage management as much as the risk department • The information flow between CEO and risk department is two way • There is a significant amount of firm specific data that should be incorporated into stress testing and risk management. • Connect a story to the risk • The event has more meaning than the date or the scenario # or the P&L • Firm risk is not portfolio risk – Hedge Appropriately • P&L is linear Risk is not • Reverse Stress Testing helps to identify the conditions for failure allowing for early warning as wells as prevention.

  29. http://www.riskmetrics.com/events/risk2009

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