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Risk Management and Hedging with Derivatives

Risk management has three steps: identify the risk, measure it honestly, and match the hedge to the loss profile. Derivatives are step three — and the wrong tool transforms risk rather than removing it: futures hedges keep both sides open, option hedges cap the loss at the premium.

نویسنده: FinScope Derivatives Editorial Team · آخرین به‌روزرسانی: ۱۶ آبان ۱۴۰۵

اهداف یادگیری

  • Choose between futures and options hedges by loss profile
  • Compute VaR in three methods and interpret its limits
  • Use CVaR and stress testing as mandatory complements

پیش‌نیازها

Futures and Forwards: Fair Value, Basis and Margin · Option Pricing and the Greeks

Choosing the hedge: capped vs two-sided

A futures hedge neutralizes both sides — upside and downside go together. A purchased option caps the loss at the premium and keeps upside open: it is insurance, not a risk exchange. Selling options earns premium but accepts a fat downside tail; as a hedge it makes sense mainly inside structures (a collar: buy put, sell call) that trade capped upside for cheaper protection. The right choice starts from the loss profile of the real exposure, not from instrument prices.

  • Two-sided risk, full removal → futures/forwards sized by minimum-variance ratio.
  • Protect from loss, keep upside → purchased put/call (insurance with a known premium).
  • Premium too rich → collar or spread (accept capped upside).
  • Contractual rate risk → IRS or caps/floors on the reference rate.

Measurement: VaR, CVaR and stress testing

VaR at confidence α over horizon h is a single number: the loss not exceeded with probability 1−α. Three routes: historical (empirical distribution), parametric (normal/lognormal with variance-covariance) and Monte Carlo. VaR's structural weaknesses: it says nothing about the tail beyond the cut, and it is not additive. CVaR — the mean loss in the worst 1−α — fixes both to a large degree and is coherent under distribution shape. Stress testing inverts the question: 'if this scenario happens, what is the loss?' — and because you build the scenarios, it sees what VaR cannot by definition.

VaR_α,h = z_α × σ_h × V (parametric normal)
σ_h = σ_annual × √(h/252)
CVaR_α = E[loss | loss > VaR_α]
The parametric formula is only as good as the normality of the distribution; under fat tails, historical VaR/CVaR is the minimum replacement.

Worked example: parametric VaR on a 10m portfolio

  1. V = $10,000,000; annual vol σ = 18%; horizon 10 days; α = 99% → z = 2.33.
  2. Horizon vol: σ_h = 0.18 × √(10/252) = 3.58%.
  3. VaR = 2.33 × 0.0358 × 10M ≈ $835,000.
  4. Interpretation: in normal conditions, 10-day losses exceed ~$835k with 1% probability — it is not a worst-case loss.

نتیجه: VaR is probabilistic and conditional; in real crises (correlation breakdown, fat tails) losses can be multiples of it. That is why institutional practice pairs VaR with CVaR and stress testing.

پرسش‌های متداول

Which VaR should I report — 95% or 99%?

Both: 95% for day-to-day management, 99% for capital and tail visibility. Reporting a single parametric-normal VaR on a derivatives book is misleading.

Why is option hedging more expensive than futures?

Because it keeps the upside: the premium is the insurance price. Collars reduce the cost by selling a distant call — accepting capped upside. You are choosing how much upside to give away.

How should I design stress scenarios?

Two families: historical replays (apply a real crisis to today's book) and hypothetical shocks (hand-built moves in rates, FX, liquidity and correlations). Apply them to your actual portfolio and count margin and liquidity effects, not just mark-to-market.

منابع

  1. Jorion, P. (2007). Value at Risk (3rd ed.). McGraw-Hill.
  2. McNeil, A., Frey, R., & Embrechts, P. (2015). Quantitative Risk Management. Princeton.
  3. Basel Committee, FRTB (conceptual reference).

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