Stress Testing for Geopolitical Shocks

Stress Testing for Geopolitical Shocks
Stress testing (Stress Testing) of a portfolio for geopolitical scenarios is a necessary component of institutional risk management, allowing the assessment of potential losses in the event of extreme but plausible events. Unlike standard VaR analysis (Value at Risk), which is based on historical data and assumes a normal distribution of returns, stress testing purposefully models tail risks (Tail Risks)—events with low probability (1–5%), but potentially catastrophic consequences for the portfolio. Nassim Taleb called such events “Black Swans,” although many geopolitical risks are more accurately described as “Gray Rhinos”—clearly visible, but ignored threats.

Building "What If" Scenarios
The methodology of scenario analysis (Scenario Analysis) includes three fundamentally different types of scenarios, each serving its own analytical function.

• Historical Scenarios—reproduction of market conditions during past crises: applying to the current portfolio the movements of market factors observed during specific events (the invasion of Iraq in Kuwait 1990, September 11, 2001, the global financial crisis 2008, the COVID-19 pandemic 2020, the start of the conflict in Ukraine 2022).
  Advantage: realistic correlations among assets under stress.
  Shortcoming: future crises never exactly repeat the past.
• Hypothetical Scenarios—modeling events that have not yet happened, but are plausible: military conflict in the Taiwan Strait, a major cyberattack on financial infrastructure, sovereign default in a large Eurozone economy, nuclear escalation.
  Advantage: preparation for the unknown.
  Shortcoming: subjectivity in estimating shock parameters.
• Reverse Stress Tests—definition of scenarios under which the portfolio loses a set percentage of its value (for example, 30% or 50%).
  Advantage: identification of hidden vulnerabilities and concentration risks.

To construct hypothetical geopolitical scenarios, an impact matrix (Impact Matrix) is used: the vertical axis lists types of events (military conflict, sanction shock, trade war, technological ban, terrorist act, pandemic), and the horizontal axis lists affected asset classes and risk factors (developed market equities, EM equities, government bonds, credit spreads, currencies, commodities, volatility). Each cell of the matrix contains a quantitative assessment of direction and scale of impact in the base and stress scenarios: for example, “Taiwan Strait conflict → global equities: –15% (base) / –30% (severe),” “large-scale sanctions against China → yuan: –8/–15%, offshore yuan CNH: –10/–20%, Chinese equities (CSI 300): –25/–40%.”

Key geopolitical scenarios that every manager of a large portfolio must include in the stress-testing program:

1. Escalation of conflict in the Taiwan Strait—from naval blockade to full-scale military operation;
2. Closure of the Strait of Hormuz—oil supply shock $150–200/barrel;
3. Massive cyber conflict—attack on payment systems, exchanges, custodians (systemic risk event similar to SolarWinds, but in the financial sector);
4. Sovereign crisis in the Eurozone—default or debt restructuring of Italy/Spain with the risk of currency union breakup;
5. Nuclear escalation—use of tactical nuclear weapons in any conflict (extreme tail risk with catastrophic consequences for all assets except gold and UST).

For each scenario, probability (on 1 year and 5 year horizons), timeframe for development (acute phase and recovery), and cascading consequences (secondary effects) are determined.

Reverse stress tests (Reverse Stress Test) pose a fundamentally different question: not “what will happen to the portfolio under scenario X?” but “what scenario (or combination of scenarios) must occur for the portfolio to lose 30/50% of its value?” This approach is especially valuable for identifying hidden vulnerabilities: concentration of exposure in one region or sector, dependency on a specific counterparty or custodian, correlation between supposedly uncorrelated assets under stress conditions (Correlation Breakdown—a phenomenon where correlations dramatically increase during crisis periods, destroying assumed diversification).

Concentration risk (Concentration Risk) is the most frequent cause of catastrophic losses in large portfolios.

Portfolio Stress Testing: Methodology and Practice
Technically, portfolio stress testing is performed through three main approaches with varying degrees of accuracy and computational complexity.

• Full Revaluation (Full Revaluation)—the most accurate method: recalculation of the fair value of each portfolio position (stocks, bonds, derivatives, alternative investments) under the set shocks of risk factors (interest rates, credit spreads, currency rates, volatility, commodity prices). For a portfolio with derivatives (options, swaps, structured products), full revaluation is the only correct approach, since linear approximations do not account for the nonlinearity of the option price function.
• Sensitivity Analysis (Sensitivity Analysis)—a faster but less accurate method: estimation of linear impact of shocks through factor exposures (betas), durations, option Greeks (delta, gamma, vega).
• Monte Carlo Simulation (Monte Carlo Simulation)—generation of tens of thousands of random scenarios based on specified distributions of risk factors, taking into account fat tails (distributions with heavy tails), skewness (asymmetry), and the change of correlations under stress.

A critically important but often underestimated aspect of stress testing is modeling correlations under stress conditions (Stress Correlations). In normal market conditions, the correlation between stocks and government bonds is negative (bonds act as a “safety cushion,” rising during stock declines), which provides diversification in the classic 60/40 portfolio. However, in an inflationary shock or loss of confidence in fiscal policy, the stock-bond correlation can turn positive: both stocks and bonds fall simultaneously, as happened in 2022 (S&P 500 –19%, Bloomberg US Agg Bond Index –13%)—for the first time in 50 years both traditional parts of the portfolio showed significant losses in the same year.

To model such regimes, regime-switching models (Regime-Switching Models, Markov Switching) are used, which allow for different correlation matrices and volatility parameters for different market regimes (low volatility/high growth, high volatility/recession, stagflation).

Liquidity Stress Test
A liquidity stress test (Liquidity Stress Test) assesses the portfolio’s ability to withstand large outflows, margin calls, or the need for reallocation without forced asset sales at discounted prices (Fire Sale). For a large portfolio ($100M+), liquidity is measured not only by bid-ask spreads, but also by market depth (Market Depth): the market’s ability to absorb a large sale without significant price impact (Market Impact).

Institutional risk management rule: liquidation of a position should not exceed 10–20% of the average daily trading volume (ADV—Average Daily Volume) for the instrument; otherwise, market impact significantly increases the actual cost of liquidation. For alternative investments (PE, real estate, hedge funds with lock-up), liquidity stress tests are especially important: these assets can become completely illiquid in a crisis, creating a denominator effect—disproportionately high share of illiquid assets in the portfolio after liquidation of liquid ones.

Hedging with Options, Gold, and Safe-Haven Currencies
Options hedging strategies (Options Hedging) provide the most flexible protection against geopolitical shocks. Buying put options on equity indices (S&P 500, Euro Stoxx 50, Hang Seng) protects against declines while maintaining upside potential. Buying call options on VIX monetizes the growth of volatility during shocks. Put spread (buying a put with a strike price –5% and selling a put –20%) lowers hedging costs by limiting the range of protection. Collar (buying a put + selling a call) finances protection by giving up part of the upside potential.

Hedging cost (Hedging Cost) is determined by time decay and implied volatility (Implied Volatility). With low volatility (VIX less than 15) annual protection put cost is 1.5–2.5% of notional; with high volatility (VIX more than 25) — 3–5%. The optimal solution is a systematic hedging program (Systematic Hedging Program) with scheduled option purchases (rolling quarterly puts), eliminating behavioral errors of reactive hedging in peak panic.

Gold (Gold) is the classic hedge against geopolitical risks, the “asset of last resort” (Asset of Last Resort). It carries no counterparty credit risk, cannot be frozen by sanctions, and has limited supply. Optimal allocation: 5–15% of the portfolio. Instruments: physical gold in vaults in several jurisdictions, ETF (GLD, IAU), COMEX futures, shares of gold miners (GDX) with leverage 2–3x to spot gold.

Safe-haven currencies (Safe-Haven Currencies)—CHF, JPY, and USD—strengthen during periods of stress. Mechanisms: capital repatriation by Japanese investors and closure of carry trades (JPY); inflow of funds into the Swiss banking system (CHF); global demand for dollar liquidity (USD). Currency options (call CHF/USD, call JPY/USD) are a cost-effective tool for tail risk hedging.

Geopolitical Risk Monitoring Tools
The Geopolitical Risk Index (GPR Index), developed by Fed economists Caldara and Iacoviello, analyzes the frequency of mentions of threats in global newspapers. It is divided into GPR Threats and GPR Acts. Correlates with market volatility, oil prices, and capital outflows from EM.

Professional tools: ACLED—database of conflicts with geolocation; BlackRock Geopolitical Risk Dashboard; Eurasia Group Top Risks; SIPRI—military expenditure data; GDELT Project—real-time event analysis.

Practical recommendation: formation of a Geopolitical Committee (Geopolitical Committee) for monthly risk reviews, updating stress-test scenarios, and assessing hedging. Composition: CIO, Chief Risk Officer (CRO), political analyst, fixed income portfolio manager, derivatives specialist.

Systematic and quantitative approach is the key to integrating geopolitical analysis into the investment process.