FRM II 全科目思维导图
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Market Risk
VAR and Other Risk Measures
Parametric And Non-parametric Methods Of Estimation
Non-parametric Methods
Historical Simulation Approach
Basic HS
95% VAR is the (n*5%+1)th
highest observation.
Expected Shortfall (Conditional VAR)
定义:expected value of the loss when it exceeds VAR
A <b><u><font color="#ffffcc">subadditive</font></u> </b>risk
measure.
not ambiguous.
has only one correct answer
Bootstrap Historical Simulation
will often be more accurate than a 'raw' sample estimate
Weighted Historic Simulation Approaches
Age-weighted Historic Simulation
hybrid of EWMA & HS
Advantages
Generalizes standard HS,
traditional HS is a special case with zero decay, or lambda --> 1
More responsive to large losses, also better
at handling clusters of large losses.
Reduce distortions caused by events that are unlikely to
recur; helps to reduce ghost effects.
Gives us the option of letting our sample size grow over
time.
Volatility-weighted Historical Simulation
定义式
Advantages
• Directly accounts for volatility changes
• Allows us to incorporate GARCH forecasts
• Can obtain VAR or ES estimates that can exceed maximum loss in actual datasets
• Empirical evidence to support superiority of estimates
Correlation-weighted Historical Simulation
特点
Takes account of correlations as well as volatilities
More complex than volatility-weighted historical simulation but with the same principle.
定义式
Filtered historical simulation
特点和优势
Semi-parametric bootstrap
combine benefits of historical simulation with power/flexibility of conditional volatility models (GARCH).
Bootstrapping
keeps the non-parametric nature of HS, while volatility model gives a sophisticated treatment of volatility.
Get VAR and ES estimates that exceed the maximum historical loss in data set.
Sensitive to changes of market conditions.
Advantages And Disadvantages
Advantages
•Handle non-normal returns (skew and kurtosis) •Handle any position type including derivatives •Relatively easy to implement •No "curse of dimensionality" •Uses readily available data (returns, volatility) •Easy to generate confidence intervals •Can be combined with parametric "add-ons”
Disadvantages
•Quiet period VAR (or ES) estimates will be low •Difficult for in-sample shifts or regime changes •Dominated by extreme losses unlikely to occur •Most are subject to ghost effect (shadow effect) •Plausible events that might occur but did not •Constrained by largest loss in historical dataset
Parametric Estimation Approaches
Normal VAR
VAR for returns that follows a normal distribution.
计算式
Log Normal VAR
VAR for asset prices follow a lognormal distribution.
计算式
Other Issues
Coherent Risk Measures
More general than VAR or ES
特征
单调性
If a portfolio has systematically lower values than another it must have greater risk. Standard deviation violates the monotonicity condition.
平移不变性
Adding cash k to a portfolio should reduce its risk by k. This reduces the lowest portfolio value. As with X, k is measured in dollars.
同质性
Increasing the size of a portfolio by a factor b should scale its risk measure by the same factor b. This property applies to the standard deviation.
次可加性
The risk of a portfolio is less than the sum of separate risks. Merging portfolios not increase risk.
VAR is not sub-additive. Therefore, VAR is not a coherent risk measure.
Method Of Estimating Coherent Risk
Spectral measures
Estimated as a weighted average of the quantiles (i.e.z the VaRs). The particulars of the weighting function are not important
ES
The easiest case of coherent risk measure. It gives all tail-loss quantiles an equal weight, and other quantiles a weight of 0.
More general Coherent Risk Measure
Replace the equal weights in the with a more complicated weighting function.
The estimated risk measure rises with n, and eventually converges to the true value.
More sensitive to the value of n than ES because if n becomes larger the quantiles will be more concentrated in the tail, which represent a more weighted-average extreme value of the distribution.
Standard Errors Of Coherent Risk Measures
The presence of heavy tails might make ES estimators less accurate than VAR estimators.
估计方法
L-estimator
Bootstrap
Quantile-Quantile Plots
QQ图
记忆:正S形是瘦尾
Extreme Value
三种主要理论
<b>Generalized Extreme Value Distribution</b> (Block Maxima Method)
参数
示意图
According to <b>Fisher-Tippett theorem</b>, as the sample size n gets large, the distribution of extremes converges to the generalized extreme value (GEV) distribution
Block Maxima. Classical
<b>Generalized Pareto Distribution</b> (Peaks over Threshold)
参数
计算式
示意图
Multivariate EVT
Models the tails of multivariate distributions
Key issue is the (tail) dependence structure of the extreme events
USE Copulas
It is important if extreme events are not independent
相同点
(1)Have the same goal
(2)Built on the same general principles
(3)They even share the same shape parameter: £ (Shape/Tail)
优缺点
POT better
(1)GEV involves an additional parameter:location
(2)GEV can involve some loss of useful data as some blocks might have more than one extreme
GEV better
POT requires to choosing the threshold
Backtesting VAR
定义
Compare the <b>estimated loss </b>from the calculated VAR with the <b>actual losses realized</b> at the end of the specified time horizon.
Backtesting的困难
Canot tell us with 100 % confidence whether our model is good or bad
VAR assumes a static portfolio(静态组合)<br>
怎么解决
Contamination<font face="楷体">(污染,混合)</font> minimized in short horizons<br>
Risk manager should track both the actual portfolio return and the hypothetical return <br>
Sometimes a <b><i><u>cleaned-return</u></i></b> approximation is used: actual return minus fees/commissions/net income
分类
Unconditional Coverage Model
ignores time variation,reflects the "independence" assumption
方法
直接分布法
X:the proportion of times VAR is exceeded in a given sample.
f(x)
流程
实例
假设检验法
Conditional Coverage Model
considering whether exceptions come in clusters
方法
H0: accurate model
统计量
If LR><b><u>3.84</u></b>, we would <b>reject</b> the hypothesis that the model is correct.
The Basel Rules For Backtesting
10-days 99% VAR over 250 observations
标准区间
处理方法
Basic integrity of the madel(模型基本面错误)<br>
The penalty should apply
Model accuracy could be improved(模型精确度不足)<br>
The penalty should apply
Intraday(日内交易导致头寸变化)<br>
The penalty should be considered
Bad luck
Markets were particularly volatile or correlations changed
VAR Mapping
为什么要VAR Mapping<br>
风险可归因:Positions can be simplified to smaller number of positions on set of primitive (elementary) risk factors<br>
产品特征时变:Only solution when instrument characteristics change over time.
数据短缺:Sometimes only solution to data (shortage) problem
Approaches to mapping(选哪个期限的y的问题)<br>
Principal mapping<br>
bond risk is associated with the maturity of the principal payment only
Duration mapping<br>
the risk is associated with that of a zero-coupon bond with<br>maturity equal to the bond duration
Cashflow mapping
the risk of fixed-income instruments is decomposed into the <br>risk of each of the bond cash flows
计算
Delta-normal method
Bond
公式
推导
Option
公式
推导
Delta-Gamma method
Bond
公式
推导
Option
公式
推导
综合应用
选期限-定y的VAR-用公式计算资产的VAR
Other Issues
Stress Test
过程
Relative VAR
公式
Correlation Risk Modeling and Management
线性状况下
定义
<b><font color="#ffcc99">Wrong-way risk</font></b>: adverse correlation between a bond issuer and the bond insurer<br>
影响p因素<br>
nonfinancial variables
Sovereign debt and currency value <br>
Geopolitical tensions<br>
Correlated markets and economies
解决方法
Hedge<br>
Multi-Asset Options
Option on the better of two. Payoff =max (S1, S2)
<b><font color="#fdb813">Option on the worse of two</font></b>. Payoff =min (S1, S2)
只有这个是ρ越小越好
Call on the maximum of two. Payoff =max [0, max (S1, S2)-K]
Exchange option (as a convertible bond). Payoff =max (0, (S2-S1))
Spread call option. Payoff =max [0, (S2-S1) - K]
BulletOption on the better of two or cash. Payoff =max (S1, S2, cash )
Dual-strike call option. Payoff =max (0, S1-K1, S2-K2)
Quanto option
作用
Protects an investor against currency risk
原理
举例:中国投资一家美国的进出口公司
判断Option价值的两个要素
How deep in the money ( S和K的关系 )
Exchange rate
直接对冲ρ
Corelation Swap
方法
Fixed correlation <---> Realized/stochastic correlation
计算Realized/stochastic correlation
效果
子主题
间接对冲sigma(波动率)
原因:波动率和ρ存在正相关关系
方法
Buy Call On Index and Sell Call On Individual
Variance Swap<br>
-pay fixed in a variance swap on an index and<br>-to receive fixed in variance swaps on individual components of the index.
一些结论
Equity Correlation
均值回归和趋势
非线性状况下
Copulas Function
目的
simplify statistical problems 简化统计过程<br>
multiple univariate distributions —> single multivariate distribution
n-dimensional function \rightarrow unit-dimensional one
定义式
计算方法(了解)
正态分布(高斯Copulas)
推导过程
非正态分布(Mapping分布的思想)
推导过程
Academic Literature On Risk Measuring
理论
Time Horizon<br>
取决于portfolio liquidity and purpose for risk measurement<br>
accuracy of simple VAR measures diminish as time horizon lengthens<br>
Backtesting VAR<br>
less effective over longer time horizons<br>
conditional backtests improve power of backtests
Liquidity Risk<br>
Exogenous liquidity<br>
transaction costs ---> "liquidity-adjusted VAR" approach <br>
Endogenous liquidity
price impact ---> depends on trade size(move market prices)
外生流动性风险原因
underlying asset is not very liquid <br>
size of the position<br>
small investors follow the same hedging strategy<br>
asymmetric information→magnifies the sensitivity of prices to clusters of similar trade
实践
Compare Risk Measures Methods<br>
Value at Risk(VAR)→not subadditive<br>
Expected Shortfall→ subadditive<br>
Spectral risk measures→generalization of expected shortal
bank's risk assessment framework<br>
分解结构:compartmentalized approach<br>
整体结构:unified approach<br>
Top-down Vs. Bottom-up<br>
top-down approach: risks are separable and can be aggregated in some way<br>
bottom-up approach: better account for the interaction among risk factors
Risk Management Of Fixed Income and Option
The Science Of Term Structure Models
Bond Valuation<br>
Discounted Future CF<br>
计算
Cashflow是约定的,风险来自rate的变化 --> Duration衡量
Duration
利率平行移动
不含权,持有至到期不违约,CF确定
Mac. Duration
以现金流现值为权重
一般表达式
Mod. Duration
计算
BV01: 当Δy=0.01%时的Dollar Duration
关联:通过求导关联
推导过程
所有情况,可含权
Effective Duration
利率非平行移动
Key rate Duration
Convexity
特征
正负
含权债
Callable
可以为负值
Putable
More Convexity
不含权债
正值
涨多跌少
与 Duration关系:同涨同跌
影响因素(导致上涨)
Long Maturity(夜长梦多)
Low Coupon(钱少事多)
Low Yield(世道艰难)
当Duration相同时,CF越分散,Convexity越大
Portfoliop
Barbell
短期+长期,中期少(Convexty)比较大
Bullet
集中于中期
通过D和C求解的P和真实的P的关系(当Δy变化时)
Term Structure Models
固守工具分类
不含权债
含权债
Callable bond
Putable bond
不含权债期权
call on bond
put on bond
二叉树定价法
股票二叉树(一级内容)
二叉树求法
利率二叉树
结构
注意点
节点利率管后面的时间
每个节点现金流莫忘加入Coupon
分债券种类运算
Pure Bond
运算过程
运算过程
Callable / Putable Bond
运算过程
Option On Bond
分类
欧式
运算过程
注意
求的是期权费
除了最后一期求B的现值步骤,其他不需要理会Coupon
美式
运算过程
注意
每个节点还是要加入Coupon求解B现值,然后再用现值和执行价求出当下行权的情况下,期权价值C1
和欧式一样,用期权费直接折现,求出未来再行权的情况下,期权价值C0<br>
取max(C0,C1),作为当前节点的期权价值,往前折现
为什么不用BSM求Option On Bond价值
BSM要求价格正态分布,也就是无上限
债券价格有上限
BSM要求无风险利率恒定
债券要考虑利率变动
BSM要求波动率恒定
债券波动率随到期日临近而趋于稳定
Term Structure Thoerys
Pure Expectation
F1是S1的函数
不能解释为什么利率时间曲线总是上扬,忽略了债券的投资风险
Liquidity Preference<br>
预期包含了liquidity premium<br>
Market Segmentation<br>
shape of the yield curve→>preferences of borrowers and lenders<br>
Yield at each maturity is determined independently
Preferred habitat<br>
forward rates represent expected future spot rates plus a premium(not related to maturity)<br>
explain almost any yield curve shape
Term Structure Art : Drift
Model 1 : Model with no Drift<br>
表达式
Model 2 : Model with Drift(有趋势项)
一般表达式
当λ时变时
Ho-Lee Model
表达式
当σ时变时
表达式
Model 3 : Mean Reverting
Vasicek Model<br>
表达式
θ和λ的关系
参数含义
k : 均值回归的速度
θ : long-run value of the short-term rate assuming risk neutrality<br>
r : current interest rate level<br>
Cox-Ingersol-Ross(CIR)Model<br>
适用情景:σ与r是相关的
表达式
Model 4 : Lognormal Model
原型表达式
变形表达式
表达式1
表达式2
注意点
Ho-Lee model, the drift terms are additive<br>
Lognormal model, the drift terms are multiplicative
一些结论
Interest Rate Volatility<br>
Volatility of expected rates causes the future spot rates to be lower
Convexity Effect(Jensen's inequality)<br>
表达式
The value of convexity increases with maturity and volatility<br>
Empirical Approaches To Risk Metrics And Hedging
DV01中性对冲
依赖利率平行移动假设:parallel assumption<br>
改进方法:Regression Hege
好处
克服了DV01的假设:T-bond and the TIPS are perfectly co-dependent(y是1:1 move的)<br>
estimate how much nominal yield changes given a change in TIPS yield<br>
estimate of the volatility of the hedged portfolio
方法
一个对冲工具的推导
两个对冲工具的推导
PCA
sum of the variances of the principal components equals the sum of the variances of the individual rates<br>
principal components are uncorrelated with one another
principal components are chosen to have the maximum possible variance
Volatility Smiles
解决问题:BSM期权定价中,σ恒定的假设不满足
推导
怎样的资产价格是服从lognormal分布的
The volatility of the asset is constant<br>
The price of the asset changes smoothly with no jumps
影响σ的因素
距离到期时长
执行价格(波动率微笑刻画)
波动率微笑
执行价格K和内涵波动率σ的函数
欧式期权Call和Put的波动率微笑相同
Alternative ways of characterizing the volatility smile<br>
K/S0
Delta
没有Price Jump的波动率微笑
外汇
波动率微笑图像
价格分布图像(两边肥尾)
股票
波动率微笑图像
产生原因
leverage<br>
Firm's equity value decreases→leverage<br>increases→increases the riskness/volatility of the underlying assets
Crashophobia
stock market crash→higher premiums for put prices when the strike prices lower
价格分布图像(左肥右瘦)
有Price Jump的波动率微笑
波动率微笑图像
价格分布图像
Investment Risk
Investment Risk Management<br>
Portfolio Construction <br>
选资产
输入变量
Current Portfolio<br>
已知且确定
Alphas
背景
α是回归出来的截距项
现实中,α受到constrains及其他因素限制,所以需要对回归出来的α进行调整
Refine α
Method 1:Scaling Technique<br>
Alpha = volitivity of α * Zα * IC(预测的准确程度)
推导过程
Method 2: Trimming Technique<br>
目的:把因数据问题导致的α不准排除
方法:分布尾部域直接去掉
Method 3: Neutralization<br>
Benchmark Neutralization<br>
目的:去除数据问题导致的Benchmark的收益不准确
Cash-Neutral Alphas<br>
目的:去除保留现金带来的α,这部分是择时收益
Risk-Factor-NeutralAlphas<br>
目的:消除基金经理运气导致的alpha
Alpha Converge
问题提出原因:Portfolio和Benchmark有部分重叠
处理方法
P有B没有
benchmark weight of zero<br>
B有P没有
Alphas can be inferred<br>
Covariance Estimates
一级的内容
Transaction Costs
MCVA
α - 2λ * σα * Δσα(MCAR)
-(cost of selling)< MCVA<(cost of purchase)<br>
No-trade range for alpha<br>
推导过程
Active Risk Aversion(风险厌恶)
Active Risk Aversion(λ) = IR/(2*σ of α)
推导过程
选资产的方法
Method 1: Screens<br>
方法:直接根据α大小选出最好的资产
缺陷
lgnore all information<br>
biases in the alphas<br>
lgnore certain industry with low alpha<br>
fails in addressing risk control purposes
Method 2:Stratification(分层)<br>
方法:先分层,再取α最好的
优点:solved the problem of the possible exclusion of some categories of assets<br>
缺点:Still suffers from possible errors in measuring alphas.<br>
Method 3: Linear Programming<br>
方法:多条件排序
优点:与Benchmark更接近
缺点:can be different from the benchmark with respect to the number of assets and risk characteristics.<br>
Method 4: Quadratic Programming<br>
Explicitly considers alpha, risk, and transactions costs. <br>
● Ultimate approach(终极方法)
Dispersion问题
产生原因
Client Driven
PLack of attention to separate accounts<br>
表现
同一基金经理在不同的客户账户上的投资表现不同
消失条件
交易成本为0
定权重
马科维茨有效前沿
图示
推导
Portfolio Risk
Portfolio VAR
常规的VAR
<b>公式</b>
变形
Diversified VAR<br>
Undiversified VAR<br>
衍生VAR
MVaR
含义:多投入i资产一单位,VaR的变化量
推导过程
Incremental VaR
含义:多投入任意金额的i资产,VaR的变化量
IVaR = VaR(i + P) - VaR(P) = i( dollar) * MVaR(i)
Component VaR
含义:i资产变化确定金额的数量Pi, VaR的变化
CVaR = MVaR(i) * Pi = β * VaR(P) * w(i)
Pecentage Contribution = CVaR(i) / VaR(P) = β * w(i)
Managing Portfolios Using VAR<br>
Reducing positions with the highest marginal/ VAR.<br>
Increase position with highest SR<br>
Types Of Risk<br>
Absolute Risk<br>
Policy-mix risk<br>
IPS决定的风险,是风险的主要构成
Active-management risk<br>
执行偏差风险,相对较小
Relative Risk
Types
Cash-flow risk <br>
Economic risk
Funding Risk
相当于资产与负债的组合,形成了相对风险
VAR And Risk Budgeting<br>
VaR什么时候更有用
the horizon is short, turnover rapid, and leverage high<br>
风险预算
原则:Top-down allocation<br>
步骤
Budgeting across Asset Classes<br>
maximize return at a targeted level of risk<br>
Budgeting across Active Managers<br>
weight of porfolio managed by manager i<br>
Risk Monitoring And Performance Measurement
步骤
机构:RMU
注意:Liquidity duration<br>
用途:衡量需要交易的资产在不影响市场的前提下,执行完毕需要的时间
公式:LD = Q/(0.15V)
Q:需要交易的资产总量
V:一天内该资产的市场总成交量
Portfolio Performance Evaluation
目的:看完风险,也看看收益
考虑外部现金流(基金购入或赎回)的Return计算
Time-Weighted
计算思路:根据中间现金流时间切开时段
注意:T和切几段没有关系
not affected by cash inflows or outflows<br>
Dollar-Weighted
就是求IRR
现金流可以有效控制时适用
Risk-adjusted Performance Measures<br>
基础指标
Total Risk
Sharp Ratio
公式
M Square
公式
注意:M Square 和 SR的排序是一样的,求M不方便可以直接求SR
Systematic Risk
Treynor Ratio
公式
Jenson's Alpha
公式
Non-Systermatic Risk
Information Ratio
公式
高级计量
Market Timing(择时能力)
No Market Timing Model<br>
表达式
特征:P和M线性相关
Treynor and Mazuy Model
表达式
特征:二次凸性,C>0时,Good Timing
Henriksson and Merton Model<br>
表达式
特征:分段凸性,牛市D=1;熊市D=0
Call Option Model
Value of appropriate fee for perfect foresight should equal to the price of the call option on the market index
Style Analysis(风格分析)
分类:Value vs Growth / Large vs Small
方法:四因子回归,系数大的是显性风格
Performance Attribution(归因)
α来源分类
selection of the right asset classes(sectors)-选行业<br>
selection of right securities within an asset class.-选个股
归因计算方法
附加话题
α假设检验
方法
对冲基金的分析困难
quickly change investment strategy <br>
illiquid assets that are difficult to price
provide profits over a long period of time, but expose the fund to infrequent losses
Survivorship bias
Practical Topic(关于对冲基金)<br>
Portfolio Choice With lliquid Assets(略)<br>
Iliquid Assets Three key biases<br>
Survivorship bias<br>
Infrequent Sampling<br>
Selection Bias
一个不全面的观点(flawed)
Economic theory states that there should be a premium for bearing illiquidity risk<br>
major impacts of infrequent trading on asset allocation<br>
reduces optimal holdings(因为无法及时rebalance)<br>
Rebalance lliquid Assets to Positions Below the Long-Run Average Holding<br>
Consume Less with lliquid Assets
There Are No lliquidity "Arbitrages"
Investors Must Demand High lliquidity Hurdle Rates
Hedge Funds
Biases Of Hedge Funds<br>
Measurement Bias <br>
Backfill Bias
Survivorship Bias
Selection Bias(self-reporting bias)
Hedge Fund Strategies
Managed Futuress
CTA期货策略,CTAs tend not to have a particular bias towards being net long or net short in any particular market<br>
Global Macro
盯住mis-pricing,top-down aproch,broad investment mandate,systematic or discretionary<br>
Risk Arbitrage (Merger Arbitrage)
做空收购者,做多被收购者,风险为deal risk
Fixed Income Arbitrage
Exploiting inefficiencies and price anomalies between related fixed income securities<br>
Convertible Arbitrage<br>
long可转债,short股票,因为债有凸性,irrespective of market moves.<br>
Long/Short Equity<br>
invest in both long and short sides of equity,flexibility to shift investment styles<br>
Dedicated Short Bias<br>
take more short positions than long positions focus on companies with weak cash flow<br>
Emerging Markets<br>
投资新兴市场国家
Equity Market Neutral strategy<br>
Returns differ dramatically across months. not behave like a single niche strategy. with a similar goal of achieving almost zero beta<br>
Performing Due Diligence On Specific Managers And Funds
尽职调查的四个方面
Questions To Evaluate A Manager<br>
Criteria To Assess Risk Management Process
Operational Due Diligence
Business Model Risk And Fraud Risk
Credit Risk
Introduction(识别)
The Credit Decision (略)<br>
The Credit Analyst (略)
Introduction of Credit Risk
Credit Risky Securities<br>
Credit Contract Frictions<br>
Asymmetric information (信息不对称)<br>
Principal-agent problems(委托代理问题)
Risk-Shifting (风险从股东转移给债权人)
Moral hazard(道德风险)<br>
Adverse selection(逆向选择)<br>
Externalities (外部性)<br>
Collective action problems(共同行动问题)
Default and Recovery<br>
Expected Loss
PD*LGD*Exposure
比较风险债和无风险债
1+r vs PD*RR + (1-PD)(1+r+z)
EL = PD(1-RR)
UEL = 1-RR-EL
理解:EL是损失分布的均值,UEL是损失分布的σ,即偏离均值的程度,Economic Capital覆盖的是最坏损失超过EL的部分
Market Risk 和 Credit Risk 辨析
1、由于downgrade导致的是CR
2、由于宏观环境导致的是MR
3、未说明是MR
4、Market to Market Risk 是中间地带,没有downgrade, 但市场其他债券也没有变化,是日间小变化导致的
Measurement(计量)
Credit VaR<br>
定义
示意图
定义式
EL
Worse Credit Loss
UL (Credit VaR)
Credit VaR 和 Market Risk VaR的对比
Risk Contribution
Step1 EL and UEL of of individual asset<br>
Step2 EL and UEL of Portfolio
Step3 Risk Contribution
一种简化变形
假设:每笔贷款有相同的规模和特征;ρ恒定
推导过程
当n趋于无穷大时
Step4 Economic Capital for Credit Risk<br>
注意:Credit Loss分布是highly left skew, 实务中用Beta Distribution描绘
Key Parameter<br>
PD
Historical-based Approach<br>
Binomial Trees of PD <br>
概念辨析
Marginal PD: 单年的违约率【d1, d2……】
K:正好在当年违约的概率【K2 = (1-d1)*d2】
Cumulative PD【C2 = d1 + (1-d1)d2】
Survival Rate【S2 = (1-d1)(1-d2) = 1-C2】
Average survival rate and average default rate<br>
规律
投资级别
Marginal PD 随时间变大,Cumulative PD增长速度随时间变大
投机级别
Marginal PD 随时间变小,Cumulative PD增长速度随时间变小
Credit Ratings
External Rating
评级体系图
Internal Rating
两种评级方法图示
Credit Transition Matrices<br>
信用转移矩阵计算
Credit Scoring Models
Models
Point 1: Expert systems<br>
5C法(不重要)
Point 2: Quantitative methodologies<br>
Parameter Method
Fisher Linear discriminant analysis<br>
思想:通过线性表达式把公式分为几组
典型例子:Altman's Z-Score models(了解)<br>
Parametric discrimination<br>
思想:因变量是个概率值
典型例子:logit and probit model<br>
Support vector machines<br>
Create an equation that does the best job of dividing the larger group into two subgroups.(两个超平面距离最大)<br>
Linear and Non-Linear
Non-Parameter Method
K-nearest neighbor approach<br>
K是决定看最近的几个邻居的超参数
已有正确分类的样本存在
Point 3: Decision Rules<br>
Probabilities Method<br>
1、Minimum error<br>
方法:利用贝叶斯公式判断
>时,出现C,则违约概率大;<时,出现C,则不违约概率大
Optimization Method
2、Minimum risk<br>
减少错误分类的概率及因此带来的Loss
3、Minimax<br>
minimizing the maximum error or risk.<br>
4、Neyman-Pearson<br>
错误类型
Type I :误放
Type II :误杀
减少错误的指标(拉格朗日乘数:似然比)
公式:满足时拒绝
Model Performance
The receiver operating characteristic (Roc)<br>
坐标系
X轴:False Alert Rate: Type II error / Good-Ones
Y轴:Hit Rate: Correctly Predict / Bad-Ones
图像
The cumulative accuracy profile (CAP GINI curve)<br>
图像
决策规则:The accuracy ratio(AR) is defined as AR/(AR+AP), with a ratio close to 1 implying a more accurate model.<br>
Retail Credit Risk Management<br>
零售银行特征
敞口小
风险主要是EL,可以treat this loss as a cost of doing business<br>
零售银行的Credit Models
Credit bureau scores<br>
FICO
Pooled model<br>
built by outside parties, is more costly than implementing a credit bureau score model; offers more flexibility to specific industry.<br>
Custom model<br>
created by the lender itself<br>
Market Prices Approch<br>
Infer Credit Risk from Corporate Bond Prices <br>
PD的计算
Risk-Neutral Probability of Default: YTM-Rf = PD(1-LGD)
Objective probability of default:YTM-Rf-RP = PD(1-LGD)
推导过程
Credit Spread
类型
Yield spread<br>
Bond 和 Benchmark的YTM的差
l-spead<br>
B和P期限不同时,P的YTM减去B的线性插值YTM(linearly interpolated YTM)或Swap rate
Z-spread<br>
不使用YTM,使用各自的Spot Rate计算
Option adjusted spread(OASs)
Z-spread adjusted for optionality of embedded options<br>
Asset-swap spread
Float Notes, 支付Float收到Fix,因此产生的spread<br>
CDS spread
Market premium of CDS of issuer bond<br>
Discount margin
浮动利率债券Fixed spread above current LIBOR needed to price bond correctly<br>
影响因素<br>
宏观经济影响
路径
含权影响
路径
DVCS
DV01
定义:利率变动1个Bp, 价格变动的幅度ΔP
计算公式
DVCS(Spread 01)
定义:spread变动1个Bp, 价格变动的幅度ΔP
和DV01的对比
Credit Spread Curve<br>
The first step to creating the curve is to plot the most liquid credit spreads observable in the market,generally from CDS premiums or bond spreads.<br>
Plotting the curve is further complicated by the choice of reference.<br>
An alternative method uses the credit spread around a single, liquid observation(e.g, credit spread with five years to maturity) to map the entire curve.
Infer Credit Risk from Equity Prices
Merton Model<br>
基础理论
思想
Value of equity = Call option on firm=value of firm's asset (V)-value of risky debt(执行价格是债务面值的看涨期权)<br>
Value of risky debt = Risk free debt - put option on firm
公式推导
Credit Risk计量
N(-d2)is the risk-neutral probability of default.<br>
假设A的价值是可以在公开市场观测的,而E的价格在公开市场观察不准确
σ公式推导
模型推论
Credit spread<br>
计算
当Dt已知,根据简单折现方法获得Credit Spread
推导
当Dt未知,根据莫顿模型推导Credit Spread
推导
性质
时间临近到期,Credit Spread扩大,但深度垃圾债除外
Rf上升,公司Value上升,Credit Spread减少
Subordinate Debt in Merton Model<br>
推导
次级债:好的时候是优先债, 差的时候是股,其实是一个Bull Spread期权组合(看推导)
Calculate PD and LGD<br>
PD = N(-d2) = 1-N(d2)
LGD = EL/PD ; EL用莫顿模型基本理论求解
假设和缺陷
假设
1、The value of the firm is observable and follows a lognormal diffusion process(geometric Brownian motion). <br>
2、The risk-free interest rate is constant through time.<br>
3、Debt consists of a single zero-coupon bond with a nominal payment of maturing at time T.
4、Firm can default only on the maturity date of the bond. 欧式期权
5、Equity consists of common shares only.<br>
6、Debt-holders have limited liability and have no recourse to any other assets once equity is eliminated.
7、Trading in markets occurs not only for the firm's equity and debt securities, but also for its assets.
8、There are no cash flows prior to the maturity of the debt (including dividends).
缺点
It could result in low default probability values and high recovery rates for firms with high leverage. Firms with high leverage in reality would typically have higher default probabilities and lower recovery rates.<br>
The KMV Approach<br>
放宽了莫顿模型两个假设
1、企业只有一笔零息债券负债——假设有LT和ST负债
2、企业资产价格是可观察的——资产价格是一个概率分布
模型示意图
模型步骤
Step1 : 计算Asset到Default Line的距离DD
Default Line的算法
若LT/ST<1.5
若LT/ST>1.5
DD计算公式
Step 2 : Report estimated default frequency (EDF)<br>
图中阴影部分违约概率
违约概率公式
思想:就是求N(-d2)
公式
Default Threshold: F(债务面值)
E(ROA):收益率y
V: 底层资产价值(公司资产价值)
Maturity: T-t
Step 3 : 根据EDF确定Credit Rate
Other Issues
Rating Assignment Methodologies<br>
Experts-based Approaches<br>
Structured Experts-based System: 如4C, CAMPLS<br>
Agencies'ratings<br>
Experts-based Internal Ratings Used by Banks
Statistical-based Models
Structural approaches: based on economic and financial theoretical assumptions.<br>
Reduced form approaches: use statistically suitable set of variables and disregarding the theoretical and conceptual causal relations: 如无监督学习<br>
Cash Flow Simulations<br>
Heuristic and Numerical Approaches
Heuristic methods:使用人工智能算法<br>
Numerical methods:highly complex environments下的最优化训练算法<br>
Default Intensity Models<br>
基础分布
Bernouli Trail
0/1分布
Binomial Distribution 二项分布<br>
N个独立贝努里分别的概率分布
Poisson Distribution 泊松分布<br>
λ 是1年平均违约概率
X = 0 的泊松概率是存活率
泊松分布表达式
一个例题
Exponential Distribution 指数分布<br>
描绘违约发生平均需要等待的时间
表达式
β = 1/λ
λ就是Harzard Rate, β称为Sacle Parameter
Hazard Rates<br>
定义
The hazard rate(i.e., default intensity )is represented by the(constant) parameter λ and the probability of default over the next small time interval, dt, is λdt.<br>
已知λ时计算
Survival rate<br>
Cumulative PD
Marginal PD
思路:是对Cumulative PD求一阶导
根据风险中性原理求λ
公式推导
近似公式
其中,z是CDS risk spread, 是可观察量
Hazard Rates Curve<br>
思想:λ不是时变时,时间变量是λt,相当于是矩形面积,当λ时变时,就是λ(t)函数的积分面积或分段函数下面积
LGD
Recover Rate 上升,LGD下降
影响RR的因素
EAD
Credit Exposure<br>
Credit Exposure Metrics<br>
基本概念
MtM
未来某时间点Market Value的期望(均值)
EE (Expected Exposure)<br>
MAX (0, MtM)
PFE (Potential future exposure)<br>
The worst exposure that could occur at a given time in the future at a given confidence level.<br>
Maximum PFE<br>
时间序列上最大的PFE
Expected positive exposure(EPE)<br>
时间序列上EE的均值
Negative exposure<br>
ENE
对手方视角的EPE
NEE
对手方视角的EE
Effecticve EE<br>
单调不降的EE
Effective EPE
时间序列上Effecticve EE的均值
影响因素
Future uncertainty. <br>
In situations where there is a single payout at the end of the life of a contract, uncertainty regarding the value of the final exchange increases over time.
Periodic cash flows
When cash flows occur regularly, the negative impact of the future uncertainty factor is reduced.
Combination of profiles
When the credit exposure of a product results from the combination of multiple underlying risk factors.
Optionality / Exercise decisions
Collateral
不同合约的Exposure Profiles<br>
Interest Rate Swaps<br>
两个效应
Diffusion effect(DE,扩散效应)<br>
Interest rate uncertainty 上升→DE上升
Amortization effect(AE,摊销效应)
∶Bond's duration 上升→ AE上升
Exposure变化趋势
峰值的计算推导
在此基础上再求极值
Currency Swaps<br>
推演过程
Other Security Types<br>
Loans, Bonds and Repos<br>
敞口基本上确定,但固定利率债如果市场利率下降,敞口会上升
Credit Derivatives
The increase in exposures in early years is the result of the CDS premium(or credit spread) widening. The maximum exposure for the CDS occurs at a credit event where the notional value is paid less the recovery value.
Options<br>
The general exposure profile of a long option position tends to increase until exercise due to the increased possibility that can be highly in the money <br>
Risk Mitigation Techniques<br>
Netting
The benefit of correlation<br>
Positive correlations have lower netting benefits
Negative correlations provide stronger netting benefits<br>
Netting Factor
计算
Netting benefit improves(i.e, netting factor declines)with a larger number of exposures and a lower correlation.<br>
Netting benefit also depends on the initial MtM of transactions.
Collateral
影响效果的因素
Remargin period<br>
Exposure could increase between margin calls.<br>
Threshold
Minimum transfer amount
Independent amout(initial margin)
Rounding
Counterparty Risk
Counterparty Risk Terminology<br>
Credit migration
There is mean reversion in credit quality, so the implication is that counterparties with strong credit ratings tend to deteriorate and those with weak credit ratings tend to improve.<br>
MtM
MtM=present value of all expected inflows less the present value of expected payments<br>
缓释风险的手段
Close-out <br>
立刻关闭与之所有协议
Collateralization (i.e., margining)<br>
Walkaway feature<br>
不再履行义务,亏损时有利
Mark-to-market
Diversification
Exchange and centralized clearinghouses
Netting<br>
Hedging
Credit Value Adjustment (CVA)<br>
定义
Expected value or price of counterparty credit risk. A positive value represents a cost to the counterparty that bears a greater propensity to default. <br>
计算
Risky value= risk-free value-CVA
CVA Spread
This would be a charge to the weaker counterparty. CVA as a spread= Spread of CDX×EPE<br>
影响因素
The CVA will most often increase given an increase in the credit spread.<br>
However, the impact will not be linear because default probabilities are limited to 100% Ifa counterparty is very close to default, the CVA will actually decrease slightly and in default the CVA will fall to zero.
The CVA will be lower for an upward-sloping curve compared to a flat and a downward-sloping curve, and the CVA will be higher for a downward-sloping curve compared to a flat and an upward-sloping curve.
<ol><li>Wrong-Way Risk Vs. Right-Way Risk</li></ol>
Wrong-Way Risk
PD和EAD正相关, CVA上升
Right-Way Risk
PD和EAD负相关 CVA下降
Credit VaR with a single-factor model<br>
计算方法
Portfolio Credit Risk<br>
Credit Risk Portfolio Models<br>
四大实务模型
CreditMetrics (J.P. Morgan)<br>
思路:根据评级定利率和PD,根据利率定PV of Future Value,PD* PV* LGD就是EL
Moody's KMV<br>
根据微观经济变化(企业股价变化)动态计量PD
CreditRisk+(Credit Suisse)<br>
假设只有违约是信用风险,评级下调不是,服从泊松分布,违约事件相互独立
CreditPortfolioView
根据宏观经济因子动态计量PD,用Logit Model
对比
对比表
Default Correlation for Credit Portfolios<br>
公式
推导过程
结论
缺点(Drawbacks)
The number of required calculations 计算太复杂<br>
Certain characteristics of credit positions do not fit well in the default correlation credit potfolio model. 假设太简单
The limited data for estimating defults: Firm defaults are relatively rare events. 数据稀疏
Credit VaR & Default Correlation<br>
Default corelation impacts the volatility and extreme quantiles of loss rather than the expected loss.
As a credit portfolio becomes more granular, the credit VaR decreases. However, when the default probability is low,the credit VaR is not impacted as much when the portfolio becomes more granular<br>
Single Factor Model<br>
目的:根据资产收益率的SFM推导ρ
公式
假设和推论
Assuming that each e, is not correlated with other credits, each return on asset, a, is a standard normal variate. The correlation between pairs of individual asset returns between two firm's i andj is β.B;<br>
假设
βi相互独立
αi服从标准正态分布
推论
资产之间的ρ等于βiβj
Conditional Independence<br>
Management(管理)
信用衍生品
Credit Default Swaps (CDS)<br>
Credit Event
CDS原理:买保险,买Put Option
CDS结算方式
Physical delivery<br>
坏处:Delivery squeeze 购回交付债券的时候会抬升债券市场成本<br>
好处:There is no need to determine the size of the loss
Cash delivery
算法:(100-z)%*the notional principal Z是企业残值的中间数(一般取违约发生后3个月值)<br>
好处:There is no need to own or purchase the defaulted securities
问题:A problem arises because the market price is fluid(价格不稳定)
CDS的衍生形态
Basket credit default swap<br>
First-to-default basket swap<br>
Nth-to-default basket swap(N>=2)<br>
定价模型:One-factor Gaussian copula model for time to default<br>
Senior basket CDS & Subordinated basket CDS<br>
结构图
CDS定价
基本原则:买CDS的PV = CDS赔付的PV
推导
CDS赔付的PV
买CDS的PV
Total Return Swaps(TRS)<br>
结构
Vulnerable Option<br>
Option holder receives the promised payment only if the value of the counterparty firm, V, is greater than the required payment on the option.<br>
The payoff : Max[Min(V, S-X),0]
If ρ(V, s)is strongly negative then vulnerable option has little value. If ρ(V, S) is strongly positive then there is no credit risk.
Derivatives With Credit Risks-Swap<br>
结构
Credit-Linked Notes<br>
第一套思路
第二套思路
结构化信用产品
Structured Products介绍<br>
Types
流程
典型结构
Waterfall Structure<br>
Senior
Junior / Mezzanine<br>
Equity
有利息现金流分配上限(OC Trigger),剩下的进入信托账户,吸收未来损失
Credit Enhancements(信用增级)<br>
Externa<br>
insurance or wraps purchased from a third party<br>
Internal
Overcollateralization (hard credit enhancement)<br>
Excess spread (soft credit enhancement)
Subordinating note classes(tranches)<br>
SPV Structures<br>
Amortizing structure(摊销还款)<br>
pass-through structure.<br>
Revolving structures(循环贷款)<br>
payments are not simply passed through.<br>
Master trust structure(共享SPV池)
Allows an SPV to make frequent issues or multiple securitizations. <br>
Enables the SPV to issue multiple ABS through the single trust.
Sell multiple issues to investors that share excess spreads over these multiple series
Performance Tools
绩效工具
Structured Credit Risk<br>
结构化产品Credit Risk的影响因素
PD
Convexity
Senior: Negtive Convexity, 在低PD区不敏感,凹离原点
Equity: Positive Convexity, 凸向原点,在高PD区不敏感
Mezzanine: 在低PD区像S,在高PD区像E<br>
对Credit VaR的影响
Correlation
对Value的影响
Equity: ρ上升,Equity Value上升
Senior:ρ下降,Senior Value上升
Mezzanine:ρ在低区像Senior, ρ在高区像Equity
对Credit VaR的影响
Other Factors
Systematic risk: high systematic risk expressed in high correlations can still severely damage a portfolio. <br>
Tranche thinness: The equity and mezzanine tranches are relatively thin.<br>
Loan granularity:Loan granularity references the loan level diversjfication.
几个概念
Default 01
计算
Implied Correlation<br>
For securitized tranches, starting with observed market prices and a pricing function for the tranches, it is possible to back out the unique implied correlation to calibrate the model price with the market price.<br>
Collateralized Debt Obligations(CDOs)
Cash-Flow CDOs
Synthetic CDOs
Risk Mitigation Techniques
Netting and Close-Out<br>
Between Two Counterparties<br>
Between Multiple Counterparties<br>
Termination Features<br>
Termination provisions 终止条款<br>
Walkaway clauses<br>
Trade compression<br>
aims to reduce the gross notional amount and the number of trades<br>
Collateral Management<br>
Central Counterparties(CCP)<br>
损失补偿顺序
Operational Risk
Operational Risk and Model Risk Management<br>
Operational Risk★★★<br>
Defining Operational Risk<br>
风险因子
分类
People(human factor)<br>
Internal processes
Systems
External events.
包含
Strategic risk and Reputational risk <br>
不i包含
Legal risk
Assessing operational risk<br>
计量方法
Basic Indicator Approach<br>
公式
注意:α = 15%
Standardized Approach<br>
计算公式
注意:分母一直是3,与Basic方法有负值时分母同步缩小不同
根据不同业务性质确定β
Alternative Standardized Approach<br>
The advanced measurement approach(AMA)<br>
计算方法
Unexpected loss in a total loss distribution that corresponds to a confidence level of 99.9% over a 1-year time horizon.<br>
分布确定方法
LDA(Loss Distribution Approach)<br>
Historical-based Loss Distribution<br>
Parametric-based LDA<br>
子分布
Loss Frequency: Poisson distribution<br>
Loss Severity: lognormal distribution (asymmetrical, fat-tailed)<br>
卷积过程
离散时
例题
连续时
Monte Carlo simulation Process.<br>
General Steps of LDA<br>
Step 1: Group loss data into a business line/event type matrix <br>
Step 2: Assign every data point in the matrix an equal weight (except for split, old, and external losses and scenarios)<br>
Step 3: Model an operational risk loss distribution in each cell of the business line/event type matrix<br>
Step 4: Determine the operating risk capital requirements
The overall operational risk capital requirement would combine the results in each of the cells(no diversification benefit)
Modeling Dependence<br>
Within-cell dependencies & Between-cell dependencies<br>
Gaussian copulas are often used.<br>
Data Framework
Internal Loss Data<br>
External Loss Data<br>
Subscription Databases<br>
Internal development<br>
from media such as news or magazines.(reporting bias)<br>
Consortium Data<br>
Operational Risk data exchange Association(ORX)<br>
Vendors
数据供应商
Scenario Analysis<br>
Biases and Challenges: Presentation bias, Availability bias, Confidence bias, Huddle bias,Gaming and Inexpert opinion<br>
Business Environment and Internal Control Factors
Risk Control Self-Assessment(RCSA)<br>
Managing operational risk<br>
Expected loss(EL)<br>
Absorbed as an ongoing cost<br>
Unexpected loss(ULl)<br>
Capital
The stress loss<br>
Insurance<br>
Organizational Designs 组织机构<br>
较好的组织结构
Model Risk ★★★
Sources of Model Risk<br>
Common Model Errors<br>
假设类错误
Common Model Implementation Errors<br>
拟合类错误
Common Valuation and Estimation Errors
Inaccurate data.<br>
Incorrect sampling period length.
Liquidity and valuation problems.
Supervisory Guidance on Model Risk Management<br>
USE
Challenge from model users may be weak if the model does not materially affect their results<br>
Such challenges tend to be asymmetric, because users are less likely to challenge an outcome that results in an advantage for them.
Model Validation<br>
Three core elements<br>
Evaluation of conceptual soundness, including developmental evidence.<br>
Ongoing monitoring, including process verification and benchmarking.<br>
Outcomes analysis<br>
Case Studies<br>
Long-Term Capital Management<br>
London Whale<br>
The 2005 Credit Correlation Episode<br>
操作
Sell protection on the equity tranche of the CDX<br>
Buy protection on the junior mezzanine tranche of the CDX.
Subprime Default Models 次贷违约<br>
Principles for the Sound Management of Operational Risk
Three Lines of Defense<br>
Business line management<br>
Functionally independent corporate operational risk function(CORF):
Independent review<br>
audit or by staff independent of the process or system<br>
Relationship Between ORMF and ORMS<br>
Capital Management<br>
Risk Capital Attribution and Risk-Adjusted Performance Measurement ★★★<br>
两个概念对比
RAROC
计算方法
RAROC Assumptions<br>
RAROC Horizon<br>
Practitioners usually adopt a one-year time horizon.<br>
Default Probabilities<br>
A through-the-cycle(TTC) probability of default is more commonly used for computations involving economic capital, profitability,and strategic decisions.<br>
Confidence Level
The hurdle rate<br>
意义:投资者要求的回报率,分为普通股和优先股
计算方法
决策规则:If RAROC>hurdle rate>value creation from the project and accepted.<br>
Adjusted RAROC<br>
计算方法
Adjusted RAROC= RAROC-β(Rm - Rf)<br>
决策规则
If adjusted RAROC>Rf, then accept the project<br>
Risk Capital and Diversification<br>
A business unit that are highly correlated to the overall firm need to be allocated more risk capital<br>
Practices and Issues in Economic Capital Frameworks
Integrated Risk Management<br>
Enterprise Risk Management <br>
Risk Appetite Frameworks
Risk Culture<br>
Stress Testing Banks<br>
Capital Planning at Large Bank Holding Companies
Resilience<br>
Cyber Resilience <br>
Operational Resilience
Liquidity and Treasury Risk
Foundations of Liquidity and Treasury Risk <br>
Liquidity and Leverage
Definition of Liquidity Risk<br>
Transaction liquidity risk<br>
Problems with liquidating a position<br>
"Liquidity black hole" Phenomenon<br>
Predatory trading掠夺性交易<br>
Transparency is important for liquidity<br>
Funding Liquidity Risk(Balance Sheet Risk)
Risk that creditors either withdraw credit or change the terms that the positions have to be unwound and/or are no longer profitable.<br>
Systemic Risk<br>
In situations of severe financial stress
Measurement<br>
Transaction Liquidity Risk<br>
Characteristics used to measure market liquidity<br>
Tightness<br>
Bid-ask spread and brokers'commissions.<br>
Depth<br>
Resiliency (弹性)<br>
The length of time for which a lumpy order moves the market away from the equilibrium price.
Adverse price impact<br>
Slippage(滑点)
The deterioration in the market price induced by the amount of time it takes to get a trade done
Liquidity-Adjusted VaR<br>
思路
VaR + Liquidity Cost (LC)<br>
计算
Exogenous Price (外生价格影响)<br>
思路:外生价格影响就是Bid-Ask-Spread
计算推导
常数情况下是一般市场状态,非常数情况下是压力市场状态
LVaR大并不能说明流动性风险越大,因为里面还有VaR,因此可以剥离计算Liquidity Adjustment
the liquidity adjustment will increase(decrease)when there is an increase(decrease) in the spread, a decrease (increase) in the confidence level, and a decrease(increase) in the holding period<br>
Endogenous Price (内生价格影响)<br>
公式推导
E是弹性
Multiplying the effects<br>
两种效应相乘
清仓时间调整
动机:因为每日逐步清仓,所以要对平方根法则进行调整
Funding Liquidity Risk
Indicators of Liquidity Risk<br>
Term Spread.<br>
LIBOR(3个月)- Fed funds(1天)
TED Spread
Eurodollor LIBOR(金融机构3个月) - Treasuries(政府3个月)
Liquidity at Risk(LaR)<br>
也叫Cash flow at risk
VaR is concerned with a loss in value, LaR is concerned with a cash flow shortfall.<br>
For example, a bond hedged with a futures contract has low VAR but high LAR<br>
Factors that influence cash flow and LAR
Borrowing or lending
Margin requirements<br>
Collateral obligations
Unexpected cash flows
Changes in risk management policy
Systemic Risk
Approaches to Estimating Crisis Liquidity Risk(了解)<br>
Crash Metrics<br>
推导公式
Worst-case outcome <br>
Crisis-scenario analyses
Management<br>
不同机构流动性管理方法
Commercial Banking<br>
bank run and rollover risk<br>
Hedge Fund<br>
管理流动性风险方法
Cash<br>
Unpledged assets are assets not currently being used as collateral
Unused borrowing capacity. This is not an unfettered source of liquidity
Money Market Mutual Funds(MMMFs)
The assets can still fluctuate in value<br>
一种流动性管理方法
Financing gap = average amount of loans- average amount of core deposits<br>
三个额外话题
Leverage
The Collateral Market<br>
Margin loans<br>
financing a security transaction in which the loan is collateralized by the security<br>
Repurchase agreements<br>
Are matched pairs of the spot sale and forward repurchase of security <br>
Reverse repo transactions: finance long positions in securities, typically bonds
Securities lending<br>
One party lends a security to another in exchange for a fee, called a rebate<br>
The security lender continues to receive dividend and interest cash flows from the security
Total Return Swaps
Leverage ratio<br>
推导过程
Margin Leverage
Repurchase Agreements and Financing<br>
回购价格
i 是内生于买卖价差的,而不是事先约定的
Motivations for entering into repos<br>
Borrower
Repos offer secured short-term financing; Repo financing is cheaper but less stable.<br>
Repos offer relatively cheap sources of obtaining short-term funds.<br>
Lender
Repos offer a low risk, collateral-secured investment opportunity<br>
Lenders may also use repos(as the reverse repo side) to finance short positions in bonds.
The Collateral Market and Leverage<br>
Collateral类型
Special collateral<br>
指定抵押债券的种类
收益比GC小
常见品种是OTR(On The Run 国债)
General Collateral
不指定抵押债券的种类
收益较大,但经济危机时,GC-Spread减少
Special Spread
定义式:GC rate - Special rate<br>
Special Spreads and the Auction Cycle(国债拍卖)<br>
Spreads fluctuate over time (波动)<br>
OTR special spreads are generally narrower immeditely after an auction but wider before auctions(流动性投放作用)
Special Spreads and Rate Levels<br>
Special spreads move within a band that is capped at the GC rate and a floor of 0%
The special spread can also be smaller than the penalty for failed trades.
用Special Spread套利
套利价值公式
Liquidity Black Hole
定义
Liquidity black hole describes a situation where liquidity has dried up →As everyone wants to sell and no one wants to buy, or vice versa.<br>
原因
The Behavior of Traders<br>
交易者类型
Negative feedback traders<br>
This creates demand(supply) for the asset that restores the price to a more reasonable level.The result is that the market is liquid.<br>
Positive feedback traders
When positive feedback traders dominate the trading, market prices are liable to be unstable and the market may become one-sided and illiquid.<br>
形成Positive feedback traders的原因
Trend trading.<br>
Stop-loss rules.
Dynamic hedging.<br>
Creating options synthetically.
Margins. 强制平仓出现的卖单<br>
Predatory trading.<br>
LTCM("relative value fixed income"trade). 长期资本管理公司采用的固收期限套利策略
Leveraging and Deleveraging<br>
加杠杆和去杠杆周期
Irrational Exuberance 非理性繁荣<br>
Often the process is self-reinforcing.<br>
The Impact of Regulation<br>
A uniform regulatory environment comes with costs. All banks tend to respond in the same way to external events,<br>
The Importance of Diversity.<br>
Early Warning Indicators<br>
Measures<br>
Forward Looking Bias<br>
A leading indicator will provide information and signal potential stress prior to the occurrence of an actual event.<br>
Sharpness (敏锐度)is the granularity and specificity of a particular indicator.
Banks should also strike a balance between external and internal measures <br>
Normal and Stressed<br>
Spanning Various Time Horizons:EWI coverage cannot be static and needs to reflect various time horizons
Escalation 升级上报<br>
Reporting
Integrated Systems<br>
Thresholds
The Failure Mechanics of Dealer Banks
主要原因:Diseconomies of Scope in Risk Management 规模不经济<br>
缓释信用风险的方法
Establishing lines of bank credit 获得其他银行的授信<br>
Dedicating a buffer stock of cash and liquid securities
Laddering the maturities of its liabilities<br>
Access to secured financing from central bank facilities.
和传统商业银行的区别
the linkages via counterparty chains 有对手方风险<br>
dealer banks have no default insurance
too big to fail
Holistic Liquidity Risk Management Framework <br>
Intraday Liquidity Risk Management
日内流动性用途
Outgoing wire transfers(the largest use) 对外电汇<br>
Settlements, at PCS systems. 支付、清算、结算系统
Funding of nostro accounts 往来账
Collateral pledging. 保证金和抵押金
Asset purchases/funding. 购买资产
日内流动性来源
Cash balances.<br>
Incoming funds flow(最主要)
Intraday credit.
Central banks: as a large source of intraday credit.
FMUs and other banks may also provide intraday credit.
Liquid assets<br>
Overnight borrowings.
Fed funds, London Interbank Offered Rate (LIBOR), and Eurodollar deposits.<br>
Other term funding: Similar to overnight borrowing.
日内流动性管理
For Financial Institutions<br>
Governance of Intraday LRM<br>
three lines of defense model<br>
Treasury is the first line of defense<br>
Corporate Risk Management is the second line of defense
Internal Audit is the third line of defense
Measures for Understanding Intraday Flows<br>
Measures for Quantifying and Monitoring Risk Levels<br>
Daily Maximum Intraday Liquidity Usage <br>
Intraday Credit Relative to Tier 1 Capital
Client Intraday Credit Usage
Payment Throughput 支付吞吐量
Role of Stress Testing
Help identify key vulnerabilities and their sensitivity to external factors. <br>
Help in formulating contingency plans for how a bank might respond to an event.
Developing the technology infrastructure
For FMUs<br>
防线
The first line of defense is membership criteria 会员准入标准<br>
Monitoring the risks of their participants is the second line of defense<br>
工具
Net Debit Caps 对单一借款方的头寸限制<br>
Collateral<br>
Liquidity Savings Mechanism<br>
Settlement Windows<br>
staggered multiple settlement windows throughout the day. 错开结算时间窗口<br>
Contingent Liquidity
A mechanism to facilitate settlement in the event of a participant failure: mutualizing the default risk<br>
Monitoring Liquidity<br>
A Taxonomy of Cash Flows<br>
目的:对现金流根据时间和规模两个维度进行分类
结构图
Liquidity Options<br>
定义
The right of a holder to receive cash from, or to give cash to, the bank at predefined times and terms.<br>
和传统Option区别
传统的只关心赚钱不赚钱,赚钱也有可能流出现金流(实物交付)
Liquility Option 只关心现金流
流动性风险的新定义
现金流与预期有差别(不管高低),就是Risk
量的维度
成本维度(融资或投资成本)
Quantitative Liquidity Risk Measures<br>
TSECF & TSECCF<br>
定义
TSECF:时间序列上的预期现金流序列
TSECCF:时间序列上的累计预期现金流序列
特点
includes the cash flows from all existing contracts that comprise the assets and liabilities <br>
CFs are adjusted to consider credit risks and liquidity options<br>
CFs originated by new business increasing the assets should be included
The rollover of maturing liabilities and new bond issuances
缺点
Many of the CFs are stochastic, such that the TSECF always forecasts just the expected value of a distribution offlows<br>
The temporal distribution could produce periods of negative cumulated cash flows
Liquidity Generation Capacity 流动性创造能力<br>
分类
第一种分类法
Balance sheet expansion with secured or unsecured funding. 依赖外部条件<br>
Balance sheet shrinkage by selling assets 依赖内部条件<br>
Repo can also be considered separately and labelled as"balance sheet neutral". 依赖内部条件
第二种分类法
Balance sheet liquidity(BSL)<br>
Selling of assets (AS)<br>
Secured funding using assets as collateral and via repo (RP)
Remaining liquidity, relates to balance sheet expansion (security-unlinked non-BSL)<br>
Unsecured funding via withdrawals of committed credit lines available (USF)
第三种分类法
In the banking book<br>
All the bonds available for sale(AFS) and other assets that can be sold and/or Repoed relatively easily.<br>
In the trading book
Add stocks and some structured products to generate liquidity
The term structure of LGC<br>
TSLGC : 时间序列
TSCLGC:累计时间序列
The Term Structure of Available Assets<br>
银行业务种类的影响结构
原则:有占有权的就是Available Assets
The Term Structure of Expected Liquidity<br>
目的:汇总现金流和创造现金流的能力
定义式
The TSL must always be positive if the financial institution has to be solvent all the time.<br>
Cash Flows at Risk (CFaR)<br>
定义:一定置信区间下极端现金流偏离TSECF的距离
定义式
方法:蒙特卡洛模拟
Term Structure of Liquidity-at-Risk (TSLaR)
定义:Collection of unexpected cash flows at each date, calculated as the difference between the minimum and the average level of cash flows<br>
定义式
Liquidity Stress Testing and Liquidity Risk Reporting
Liquidity Stress Testing<br>
流动性分类
Contingent liquidity<br>
应急流动性,压力测试对象,是liquid asset buffer
Operational liquidity<br>
日常运营流动性,无法满足压力状况下需求
Restricted liquidity
特定用途流动性,无法满足压力状况下需求
Strategic liquidity
Not primarily aimed at supporting the bank during times of stress. But may be redirected to meet contingent liquidity requirement needs.<br>
压力测试模型的要素
Liquid asset buffer. <br>
Contingent liquidity that is currently in place.
Stressed outflows.
They are those assumed to occur under stress scenarios.
Stressed inflows. <br>
They are assumed to partially offset the stressed outflows.
Stressed liquid asset buffer.
Normal Liquid Asset Buffer-Stressed Cash Outflow +Stressed Cash Inflows
压力测试模型建立过程
Organizational Scope<br>
目的:确定压力测试范围
业务单元划分维度
Liquidity transfer restrictions. 转移支付限制区域<br>
Currency. 货币域
Regulatory jurisdiction. 监管区域
Planning Horizon<br>
至少12个月时间窗口
现金流测算频率:初期需要每日预测
Testing Techniques<br>
Historical statistical techniques(E.g. CFaR)<br>
Deterministic models(E.g. hypothetical liquidity stress scenarios)<br>
Monte Carlo simulation(A statistical technique)<br>
Scenario Development
Historical Scenarios<br>
Hypothetical Scenarios<br>
Distinguish between systemic and idiosyncratic risk;<br>
Distinguish between levels of severity; 区分严重程度
Clearly define the scenarios;
Consider more holistic approaches. 更全面的方法
Development of Assumptions<br>
要细分每一种情况<br>
Outputs of the Model <br>
输出内容: Stress testing assumptions; Liquidity position metrics; Prospective liquidity position metrics; Capital and performance metrics<br>
Governance and Controls
The specific roles should consist of :Asset-liability committee;Treasury; Risk management; Internal audit; Model risk management.<br>
Optimization<br>
liquidity optimization opportunity<br>
Liquidity vs. Yield
Liquidity vs. Capital
Funding optimization.
An incentive for banks to favor"sticky"funding sources 关注粘性融资渠道
Establishment a Sustainable Infrastructure<br>
IT基础设施
Integration with Other Models
与capital stress testing整合<br>
与asset liability management整合<br>
Liquidity Risk Reporting<br>
报告内容
Contingency Funding Planning(了解)
Governance and Oversight<br>
Scenarios and Liquidity Gap Analysis
Contingent Actions
Market Signals and Reputational Impact<br>
Monitoring<br>
指向EWI
Escalation Levels<br>
风险级别逐步升级管理
Data and Reporting
Day-to-day Techniques of Liquidity and Treasury Risk Management <br>
The Investment Function in Financial-Services Management
Risk Management for Changing Interest Rates: ALM and Duration
Liquidity and Reserves Management: Strategies and Policies
Managing Deposit and Non-deposit Liabilities
Liquidity Transfer Pricing: A Guide to Better Practice
International Perspective to Liquidity Risk Management<br>
US Dollar Shortage in Global Banking and International Policy Response
Covered Interest Parity Lost: Understanding the Cross-Currency Basis
Basel Accord
Introduction of Basel Accord<br>
Basic Terms<br>
Risk-Weighted Assets (RWA)<br>
计算方法:RWA=RW*NP<br>
Expected Loss and Unexpected Loss<br>
Evolution of Basel Accord<br>
Basel I<br>
Two capital requirements<br>
Total assets to capital ratio had to be less than 20<br>
Cooke ratio must exceed 8%.<br>
风险加权资产的计算
Major limitations of Basel I<br>
all corporate loans were treated the same regardless of the creditworthiness of the borrower
ignored the benefits of diversijfication.
Basel Il<br>
FrameWork
Pillar 1: Minimum Capital Requirements <br>
概要
Total capital=0.08x(credit risk RWA+market risk RWA+ operational risk RWA).
资本结构
三级资本划分
资本要求
基础要求
资本充足率计算方法
进阶要求
At least 50% of capital must be Tier1.This means there is 4% .<br>
Half of the Tier1 requirement has to be met with common equity.
资产分类
Bank Aseet
三类资产的风险计量
Credit<br>
Standardized Approach<br>
Risk weights based on external credit rating assessments.<br>
评级-权重对应表
Collateral Adjustment<br>
· The simple approach(改变RW): The risk weight of the collateral replaces the risk weight of the counterparty.
· The comprehensive approach(改变NP): Adjust the size of the exposure upward and the value of the collateral downward
Internal Rating-Based(IRB) Approaches<br>
EL的计算框架
模型推导
WCDR计算(Asymptotic Single Risk Factor(ASRF) Model)<br>
ρ的计算(了解)
MA(Maturity Adjustment计算)
参数说明
计算UL的VaR参数
1-year 的99.9% VaR
All systematic risks are modeled by a single risk factor; allidiosyncratic(unsystematic) risks tend to cancel out.<br>
公司规模越大,ρ越大;PD越大,ρ越小(坏人千人千面,系统性风险小)<br>
Maturity Adjustment:FIRB下确定2.5年,AIRP下各自计算<br>
LGD:FIRB下45%for senior claims and 75%for subordinated claims. If there is collateral, the LGD is reduced using the comprehensive approach<br>
特例:Retail exposures<br>
only a treatment like the Advanced IRB approach is used<br>
特殊规定
Banks provide internal estimates of PD, LGD and EAD. <br>
No maturity adjustment.<br>
ρ分三种情况
ρ=0.15 for residential mortgages;
ρ=0.04 for qualifying revolving assets (mostly credit card balances);
other
ρ are lower for retail than for wholesale exposures<br>
Market<br>
Standardized Measurement Method<br>
计算方法
缺点
It ignores correlations between the instruments.<br>
Internal Models Approach<br>
计算方法
参数
VaR的参数是99%的10天VaR,因此daliy VaR已知,要乘以根号10
SRC是The specific risk charge(SRC)<br>
m是根据回测得到的模型准确性调整参数
m定值方法:基底是3,根据规则调增
Operational(详见操作风险章节)
Basic Indicator Approach<br>
Standardized Approach<br>
The advanced measurement approach(AMA)
Pillar 2: Supervisory
概要: Allow regulators from different countries some discretion in how they apply the rules.
涵盖的风险
第一支柱虽涉及但未完全涵盖的风险<br>
Credit Risk<br>
Concentration risk<br>
Risk of Credit risk mitigation(CRM)
第一支柱未涉及的风险
Interest rate risk of banking
book Liquidity risk
Reputation risk
Strategic risk
Business risk<br>
外部因素<br>
Business bycle
Pillar 3: Market Discipline
要求
Increase transparency
Disclose more information about the risks<br>
Basel II.5
Stressed Value-at-Risk(SVaR)& Incremental Risk Capital Charge<br>
计算公式
参数
SVaR
用压力情境下数据计算,99% confidence level over a 10-day period<br>
250-day period of stressed market conditions.<br>
k就是巴II里面的m
IRC
计算方法
覆盖风险(内含信用风险部分)
default risk<br>
credit migration risk for debt instruments.
99.9% confidence level over one year, computed on at least a weekly basis.(参考的是信用风险的方法)<br>
发展:Comprehensive Risk Measure<br>
CRM is a single capital charge for correlation-dependent instruments that replaces the specific risk charge(SRC) and the IRC.<br>
Fundamental Review of The Trading Book<br>
proposed an alternate measure using expected shortfall(ES)<br>
every risk factor is assigned a liquidity horizon for capital calculations.<br>
计算方法
To be allocated to the trading book, the bank must prove more than an intent to trade.<br>
Basel III
改革总述
Raising capital standards, both in terms of quality and quantity.<br>
Strengthen the risk coverage of the capital for trading books and complex off-balance sheet exposures.
Requiring a leverage ratio
Promoting countercyclical buffers
Instituting policies to address systemic risk
Instituting a global liquidity standard
1、Capital Definition<br>
Tier 1 Capital<br>
1. Common equity including retained earnings(Core Tier 1 capital)<br>
2. Non-cumulative perpetual preferred stock(additional Tier 1 capital)<br>
3. Tier 1 capital is adjusted downward to reflect defined benefit pension plan deficits 养老金赤字减项
Tier 2 Capital
1. Debt subordinated to depositors with an original maturity of five years or more <br>
2. Some preferred stock, such as cumulative perpetual preferred
取消了 Tier 3 capital.
2、资本金比例要求
Capital Conservation Buffer(CCB) 资本留存超额资本<br>
Countercyclical Buffer 反周期超额资本<br>
3、Operational Risk<br>
Selecting Internal Loss Reference Dates<br>
the date of the event's occurrence, the date of discovery, the date of contingent liability, the date of the first financial impact, and the date of the settlement.
operational risk management framework(ORMF)& operational risk measurement system (ORMS)
4、Leverage Ratios<br>
The Committee will test a Tier 1 leverage ratio of 3%
5、Systematic Risk Management<br>
systemically important institutions<br>
6、Liquidity Requirements<br>
Liquidity Coverage Ratio<br>
目的:Promote short-term resilience of a bank's liquidity profile<br>
计算公式
分子:High-Quality Liquid Assets(HQLA)<br>
Level I assets
Cash, Central bank reserves, Marketable securities, Non-0% risk weightedsovereign or central bank securities.
Level2 assets
Level2A assets: A minimum 15% haircut is applied to the current marketvalue of each Level 2A asset<br>
Level2B assets: Residential mortgage-backed securities, Corporate debt securities, Common equity. A greater haircut than Level 2A assets is applied
分母:Net Cash Outflows<br>
net cash outflows=ouflows over the next 30 calendar days-<b>min(inflows,75% of outflows)</b>
Net Stable Funding Ratio(NSFR)<br>
目的:Promote resilience over a longer time frame<br>
计算公式
赋权方法
Liquidity Monitoring Tools<br>
Contractual maturity mismatch<br>
Concentration of funding
Available unencumbered assets
Liquidity coverage ratio by significant currency
Market-related monitoring tools
7、Risk Coverage<br>
Reforms are intended to address CCR (counterparty credit risk), credit value adjustments(CVA) and wrong-way risk.
2017 Basel III
1. Standardised Approach for Credit Risk<br>
使之颗粒度更细,更敏感的具体方法
2. Internal Ratings-based Approaches for Credit Risk<br>
(1) Removing the use of the advanced IRB approach for certain asset classes<br>
具体移除标准
(2) Specification of input floors: introduce minimum"floor"values for bank-estimated IRB parameters(PD,LGD,EAD)<br>
(3) Additional enhancements<br>
· for exposures secured by non-financial collateral, reducing the LGD parameters
· for unsecured exposures, reducing the LGD parameter from 45% to 40% for exposures to non-financial corporates
3. CVA Risk Framework<br>
enhance its risk sensitivity<br>
The exposure component of CVA is directly related to the price of the transactions. These prices are sensitive to variability in underlying market risk factors
strengthen its robustness<br>
Removes the use of an internally modelled approach, and consists of:(i) a standardized approach; and (il a basic approach.
improve its consistency
CVA risk is a form of market risk.The standardized and basic approaches of the revised CVA framework have been designed and calibrated to be consistent with the approaches used in the revised market risk framework.
4. Operational Risk Framework<br>
假设
Operational risk increases at an increasing rate with a bank's income;<br>
Banks which have experienced greater operational risk losses historically are assumed to be more likely to experience operational risk losses in the future.
计算方法
ORC(Minimum operational risk capital)=BIC*ILM<br>
BIC
ILM
注意
A bank's internal loss data must be comprehensive and capture all material activities and exposures. The minimum threshold is set at E20,000.<br>
A bank with losses that are high relative to its BIC is required to hold higher capital<br>
Operationalloss events related to credit risk and that are accounted for in credit risk RWAs should not be included in the loss data set.<br>
Operational risk losses related to market risk are treated as operational risk
5. Leverage Ratio Framework<br>
系统重要性银行的杠杆率要求增加0.5%
如果不能满足整个指标体系中任意一项
A G-SIB that does not meet one of these requirements will be subject to the associated minimum capital conservation requirement (expressed as a percentage of earnings).<br>
6. Output Floor<br>
IRP计算的RWA须在(RWA,72.5%标准法计算的RWA)中取孰大
Solvency ll<br>
与巴塞尔协议的区别
FrameWork
三大支柱一模一样
In Basel/II there is a stronger emphasis on the stability of the financial system(systemic risk)<br>
Solvency ll focuses on individual policyholders.
VaR Parameters<br>
巴塞尔协议
MR:99% 10天
CR/OR:99.9% 1年
Solvency
99.5% 1年
Risk Classes<br>
So/vency II comprehensively assesses all quantitatively measurable risk types, all related to underwriting risk.<br>
Minimum Capital Requirements<br>
With Basel I/II, there is only one minimum equity capital ratio requirement <br>
Solvency lI capital requirements use a two-level approach<br>
· Solvency capital requirements(SCR)<br>
· Minimum capital requirement (MCR):capital requirement is between 25-45% of the SCR.
Diversification(在什么层次做diversification)<br>
Basel I/lll only considers LevelI diversification,Solvency I considers Level1,Level 2 and Level3 diversification<br>
风险分层
Solvency lI Framework<br>
Standardized approach: Analogous to Basel Il<br>
Internal Models Approach: A VaR is calculated with a one-year time horizon and a 99.5% confidence level.<br>
· Underwriting risk<br>
· Operational risk
· Investment risk: divided into market risk and credit risk
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