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Understanding RisksIn Structured Products
Dong Qu
December 2011, Scuola Normale Superiore - Pisa
2
Table of Contents
1. Common Denominator in Structured Products Business
2. Key Risk Characteristics of Structured Products
3. Correlation vs. Contagion
3
1. Common Denominator in SP Business
Structured product business pillars:
Marketing/structuring;
Trading/risk managing;
Quantitative modeling;
Marketing/structuring: provide products to meet investors’ financial needs & risk appetites;
Trading/risk managing: hedge & mitigate risks;
Quantitative modeling: develop quantitative models to price the cost of hedging risks;
4
Risk is the Common Denominator
Capital Return Risks
Growth Products Secured Linked to Markets Option Risks
(Impact Return)
Income Products
Not Secured
Much Enhanced Yield/Income
Option Risks (Impact Capital)
CPPI(Fund)
Protected But Not Secured Linked to Markets Gap Risks
(Impact Both)
5
Quantitative Models
Quantitative models: mathematical tools to price the Risks and their hedging costs;
Good quantitative models:
Able to calibrate to the markets properly;
Able to capture key risk exposures;
Numerically stable for pricing;
Numerically stable for generating Greeks;
Computationally efficient.
6
2. Key Risk Characteristics of Structured Products
Partial Differential Equation (PDE):
Risks Embedded in Options:
Time decay – Theta;
Spot – Delta;
Spot – Gamma;
Volatility – Vega;
Rate – Rho.
VrSVS
SVSqr
tV
2
222
21
7
“Exotic” Risks Embedded in Options:
Dividend Risk;
Quanto Risk;
Volatility Skew/Smile Risk;
Gap Risk;
Hybrid Risk;
Correlation Risk.
“Exotic” Risks
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Risks That Supposed to be Trivial
Dividend Risk:
Most banks use deterministic sets of forecast dividends in pricing models;
During 2008 crises, banks had to mark down the dividends, resulted in substantial losses;
Quanto Risk:
Most banks use the simple quanto adjustment;
Again, during 2008 crises, banks’ equity positions lost lots of money on quanto (FX) exposures.
9
Quanto Hedge Becomes Difficult …
Both equity and FX vol shoot up;
Correlation shoots up;
Stochastic vol effect becomes significant;
FX smile comes into play.
Risks that supposed to be insignificant became Massive!
10
When market crashes, volatility shoots up!
DJ_STOXX50 Spot vs ImpVol
3500
3900
4300
4700
02/07/2007 26/08/2007 20/10/2007 14/12/2007 07/02/200810
20
30
40SpotImpVol
Volatility Skew/Smile Risk
11
Delta in the Presence of Skew
Equity skew effectively illustrates the correlation between Spot and Volatility;
Option delta is a function of skew:
Skew dynamics:
Sticky delta (ATM vol moves with spot);
Sticky strike (Black-Scholes delta);
Sticky local vol (Static local vol, e.g. in PDE);
SV
SV
12
Re-writing option delta:
Delta under skew dynamics:
L(t) = -1, sticky delta, real delta > BS delta;
L(t) = 0, sticky strike, real delta = BS delta;
L(t) = 1, sticky local vol, real delta < BS delta;
)(tLS
vega
SV
SV
SurfaceBSBS
Delta Hedge Under Skew Dynamics
13
Delta Under Skew Dynamics (CALL)
Delta vs Maturity (European Call)
30%
40%
50%
60%
70%
80%
90%
0 1 2 3 4 5Maturity
L = -1L = -0.5L = 0L = 0.5L = 1
14
Delta Under Skew Dynamics (PUT)
Delta vs Maturity (European Put)
-60%
-50%
-40%
-30%
-20%
-10%
0%
0 1 2 3 4 5Maturity
L = -1L = -0.5L = 0L = 0.5L = 1
15
An Example of L(t) Term Structure
L(t) Term Structure
-100%
-75%
-50%
-25%
0%
0 2 4 6 8 10Years
16
Skew Risks in Illiquid Markets
Skew risks are real:
Skew represents spot-vol correlation;
When market moves, volatility moves too!
In illiquid markets (e.g. emerging markets):
Option quotes are scarce, even for ATM;
Very difficult to obtain implied vols at various strikes;
Very little market information on volatility skew;
But the skew risks STILL exist and are REAL!
17
Gap Risks in CPPI
CPPI uses GC measure to dynamically re-balance risky assets (e.g. shares) and risk free assets (e.g. cash);
Gap Condition (GC ):
Gap Condition is simply the gap between the current fund value and promised guarantee (pv_ed);
It is effectively an investment safety buffer.
TtTt DFGVGC
18
CPPI - Dynamic Re-balance
Switching between risky and risk free assets:
If GC is large (e.g. > 25% Of Gt ), whole fund will be invested in risky assets, to fully benefit from market upside;
If GC is zero (i.e. Vt = Gt ), whole fund will be invested in cash, to fulfil the promised guarantee;
Between the two extreme cases, a portion will be invested in risky assets, with the remaining in risk free asset. The asset re-balance is conducted dynamically.
19
An Example CPPI Path
CPPI Return vs Equity Path
0%
25%
50%
75%
100%
125%
150%
0 1 2 3 4 5
Equity PathCPPI Return
20
Gap Risk
Risky Investment Proportion vs Gap Condition
0%
20%
40%
-10% -5% 0% 5% 10%
21
Hybrid Risks
Equity Linked GAO: pension & insurance products, equity + interest rate + correlation risks:
Equity & Debt Products: convertible bonds, equity + credit + correlation risks:
),max()0,max(0
grNAKSNN
TTT
TT
BCBCBCBCB VScVr
SVS
SVSqr
tV
)(
21
2
222
22
Stock markets correlation: global economy;
Credit markets correlation: global economy;
Stock/FX correlation: when markets are in distress;
Credit/FX correlation: there have always been strong links between emerging markets FX and sovereign credits;
Since credit crunch, many countries behave like emerging markets as far as credit is concerned.
3. Correlation vs. Contagion
23
Stock Markets Correlation
Stock Markets (China, Europe, USA)
1000
2000
3000
4000
5000
6000
01/01/2008 08/12/2008 15/11/2009 23/10/2010 30/09/2011600
800
1000
1200
1400
1600SHCOMPSX5ESPX
24
Credit Markets Correlation
Credit Default Swap
0
300
600
900
1200
01/01/2008 08/12/2008 15/11/2009 23/10/2010 30/09/2011
GERMANY
ITALY
Morgan Stanley
25
Stock & FX Correlation
Stock & FX Correlation
1500
2000
2500
3000
3500
4000
4500
01/01/2008 08/12/2008 15/11/2009 23/10/2010 30/09/20111.1
1.2
1.3
1.4
1.5
1.6
1.7
SX5EEURUSD
26
Credit & FX Correlation
Credit & FX Correlation
0
100
200
300
400
500
01/01/2008 08/12/2008 15/11/2009 23/10/2010 30/09/20111.1
1.3
1.5
1.7
ITALY
EURUSD
27
UK - CDS vs. FX (Credit Crunch)
During Crunch: UK (FX vs CDS)
0
40
80
120
160
200
08/08/2008 03/11/2008 29/01/2009 26/04/2009 22/07/20091.2
1.4
1.6
1.8
2.0CDSGBPUSD
28
What Happened In 2008?
Collateralized Debt Obligation (CDO): a pool of assets, with defined tranches of credit loss;
Each tranche can be sold to investors to suit their risk appetites;
The pool as a whole has no correlation risk, but pricing any single tranche CDO (STCDO) involves pricing in correlation risks;
One needs to model joint default risks (correlation);
Copula was used to model the joint default risks.
29
Sub-Prime Distribution Mechanism
All elements were in place! Ready to go!
RMBS
(Sub-Prime)CDO
Tranches
Domestic Investors
Banks
(Pricing Model)
Foreign Investors
30
CDO Lessons
There was a false sense of security – “we can now value CDOs”. The world had since sold far too much of them!
Simply because ones can value CDOs, it does NOT mean they can practically risk manage CDOs:
Hedging difficulties;
Over leveraging problems;
Correlation assumptions;
Liquidity issues;
Transparency & visibility issues;
Etc.
31
What Is Happening Now (2011/2012)?
Instead of sub-prime mortgages in USA, it’s now sovereign debts in Europe;
Very high Debt to GDP Ratio: Greece (143%), Italy (119%), etc;
In addition, GDP does not grow but decline;
Faced with huge contagion risks, let’s hope politians find answers very very soon;
In fact, the contagion risks are surprisingly similar to basket correlation risks!
32
Basket Options* Analogy
Basket correlation risks:
Cross Gamma: one underlying can affect the others;
Correlation risk: co-dependence can change;
Correlation skew risk: when markets fall, correlation shoots up;
Credit default risk: basket underlying can go bust;
* Qu, D. (2005), “Pricing Basket Options With Skew”, Wilmott Magazine, July
33
Contagion Risks
Contagion Risks: versus basket correlation risks:
Cross Gamma: one country can affect the others;
Correlation risk: co-dependence can change;
Correlation skew risk: when in crisis, countries’ co-dependency becomes much stronger, hence increases chance of “getting worse together”;
Credit default risk: a country can default.
34
Basket Correlation Contagion
The World Is Like A Correlated Basket !!
Questions?