PartI I
Assel Returns sweighted sam
⑧ Simple R += (P+ -Pt-1) /Pt- 1 st. portfolio Rpt = &2 , WiRit , where wi=
niPit-
&niPi , t-
②
Log #
= In (P+ /P+ -1) St. multiple-period h = H + - - - + F- h +
Stylized facts of asset
returns &
herizon sum
⑧ distr. of return is not normal Ke free ,
excess K: 3 : large & Small R occurs more often st. fat-tailed & peaked distr.
neg. SK
<0 : large
neg.
R occur more often than large pos. ones - which are more
freq
② almost no sign. autocar in R
③ small , but
very slowly declining
autocorr in
sq. & abs.
R
SK
####### : 3
- 6
e
- >
Normality
: SK = M3ln o
k = Myla(JB
= S + -3 Exice)
, where
R
: HEL
mj
= E((r-E(i) St .
m
= &"CH-r) j
- > Autocorr. & covar : measure
- dependence between R that are periods apart
· autocouar
· j(K) = E((r-M) (H -K - M) - > &(4) = &TiP (H+ - v) (r+ + v)
· autocar
. p(K) = f(k) /(20) - > j(k) = j(k) /Yo
=> Box-Pierce test (join sign. of 1st m autocarr. ) : Am = GL K * + X & (m) but
M+ 2 caust DE(s12+ 120
Volatility
####### Models : General sel-up #2++ Stim + It , where stWN , SEEPIIN)
= M + + Et = M + St Cassume ht = Mas time-variation in is moment diff. to capture)((st11tDa
·
Eft white noise, but O cond , mean ELE+ 11t-) = 0 anstart 2
② time-var. Can . var. ECEF17 + -1)
=O time-varying
G
· 0
ECH11+ -1) = My = M var of of an. It+:
My
② UCr11+ -1) = E((r-M +> 11 + -1) = of M - M() = E+ T
VIrel2t-
- > - Elli-Ecrt]
H-h = Et = +Et , Et "20(, 1) St . of captures temporal variation of Et -z
(2) M-MH) = 2t2cE+,Et = std . W(0, 1) IN) Of 12f1] Of
Aim : develop mic model to estim. & forecast (need to specify distr of Et)
- Use : uncon-var. of Et ELEI) = ElE(2f11+-)) = E(o]) = =
Volatility Clustering def. periods of large I small movements of prices alternate
·
volatility def-
annualized stder. of R which is not observable
Variance Crisk) o = E((H-1>2) , where M = Er
· var is
symmetric
:
weights pos,
der. from in
equally
to
neg.
dev.
- > downside (tail) risk
def. risk associated with R below expec. R
measures& Value-at-Risk (VaR) ② Expected Shartfall (ES)
Value-at-Risk-quantile - prob, that Ris expec, to be exceeded : good
def. O max. loss
(VaRt(q ,
h) = gth quantile of distr of h-day R Fithih = Het +... + With
② min R P(rhin <VaR+ (1 -g , h)) =
g (
=)
Fithin (VaR+ (1-g , h))
=
9
pros : easy to calc ; 7 always ; info. on tail risk (left & right)
cans : uninfo. on what happens once VaR has been breached (gapI break) ;
lack of sub-additivity VaRt (1-g , 1 , X + Y) > VaR+ (1-g, 1 ,X) + VaRt(1-g , 1 , Y) St. discourage diversification
- > estimation Assume all
it has same distr
& Historical simulation : let ra- ... < r() St. VaRt(1-g , 1) = regt)
1972 N+ - M
② Parametric model for uncon ·
density
- > Normal = T = M + 0zt -NC, 2) , t = o ~ N(0, i)
St. VaRt(1-g , 1) = M + zg0 - > VaRt4-aih) = Et (thin) + Eg thin
~ assume allt 100 (1 , 02 & def .
sprt rule
:
h-day VaR
Square-root-of-time Rule let Fithin
= M+ + -- + #th & #80(p , 04 St can be estim , as o time
0 ECrthin) =
hh( VaRt(g ,
h) = hi + EgoVaRt(-q , 1) I-day VaR estim.
② V (rtthih) = Gez o 11 & of constant (i = 2)
~ more info , but reg, finite ist moment & very data-intensive
Expected Shortfall - cand. expec i adressess cans of VaR
2
def. expec. loss given VaRt(-g , h) has been breached (Fthh VaRt(1-gin))
ESt(1-gih)
= E
(Fthin thin - VaRt(1-g , h))
= E(rethin
I Crithin[ VaRt(1-gih))(
- > estimation
& Hist . simulation : ESt(1-g , 7) = (t) , qTEZ
② Parametric model for uncon · density - > Normal : ESt(1-9 , 1) = 4 - Efzlzq
Estimating Oft as vola. # observ
& Historical vola.
using rolling windows F
=**CHT - r, where F = &" r+ -
- > drawbacks :
1) estim . exhibit ghost features ; of suddenly ↑ Whenever large R occurs & ↓ Whenever this R leaves
the moving window due to equal
weighting (*)
2) Sensitive to 7 ; the smaller T, the more prominent impact of culliers on R
3) assumes R over past T days have same var
② Using Exponentially Weighted Moving Aug. F = (1 = 1)[i]"(ri-F)" = Jo + (1-b) (r- 1 - F5 , 02x
- > Riskmetrics +20 . 9h
Volatility forecasts Ethi
=
H , th
forecasts made at t for future periods are equal to th
Sart-of-time rule applies when 120. 97
:
h
= Ch
Filt h
if stationary model
Volatility
Model
GARCH ( model of = w + def + Bot-110 , Et if w , 0 , By
=
innovation
- > ARMACI
, 1 : EF = w + ( + B) St + + - BV+-1 , where up = et- of & Elvf11 ++ ) = 0
M
covariance
stationary if
< + B < 1 (AR coeff. ( - >
EC) 2 B
EWMA : setting w = o , 1 - x = B = J => of = (1-5) F-1 + JOF
- > IS GARCHC
, 1) good model for of estim .? - S = of * law of prob· f(AIB) = f(A, B) (f(B)
0 Non-normality : uncan · distr of of f(rt) = (f(r+ S)ds = * ff(rts)f(s)ds = mixture of Normal # ~ N
yes!
&
② Autocarr. CauCF , +-j) = ECCF-M) (r-j - >) = E(z+ o+ E-jOj) = ElztE(t) = o
③ Autocar. of EF : If X small & X+B close to 1 : g, = X small , but decay of higher oder is slow
-even still exponential
- > estim
. GARCH : Max. Likelihood function Gy(t) = f(r, ..., Rit)indep
.
I f(rt17 +- 1 if)
st. EML , 7 = argmax(T(f) = argmax 22 , et(e) = argm. 2 In (fCHIt + ie))
· ↓
forzN(0 , 1)
:
f(zt)
= exph-f) St. C = -EInCIT-IInCOF)-CF-M72Of
- > evaluation : consider
properties of std . resid. Et
= (H-) /87 i
⑦ mean o & var. I ③ K = 3 if
normality assumed
② no autocar. in level & Sq
- > vola .
forecast 2
1) -Step : t = Elof11 += E(w +* zi + Bof11t) = w + af + Bo = o
2). 2 - Step : H = E(OF217+ ) = w + (4+ B) of as ECEtilIt) = off
n). n-Step : Ötthi = w & (h + B) : + (a+ B) h + C
ARCH(1 , 1) model of = w + EF= 0 , Et if w, do if do ; it homosk as of w
- > AR(I) : SF = W + x[f1 +
N+ , where Ut = EF- o
· ARCH
Stationary if <
: shocks have
transitory effects on fij
volatility clustering
: if 1st-
large-> 1841 expec , to be large as well
- >
volatility mean reversion
: 0 (2,% =
fraction a of (EE , 2)
*
pi
= > 0 S .t. decline
exp. towards 0 E ARCHCI) in adequate
Part 2 4
Portfolio Management diversification helps to reduce risk
risk : measure of uncertainty in asset R
- >
diversification is crucial in order to obtain higher mean R than risk-free rate
fully invested portfolios
: weights sum up to
assume ↓ <?
Variance of Portfolio Returns OPIN) = 0 F/1-pr
mmmm, 02) reduction
due to
Op + 022 - 2 p 1 2002 diversification
- > no
gains from
divers, if : 17. O, or = 0
2) 0 = 22pi = 1
3) Pi = 210 = 1 Sit. WT = 0
- the more assets are combined in a portfolio , the smaller the var of portfolio R =
O(WE , N) 1 Op(WY , M) , ANIM but this occurs at a decreasing rate & the var can't be
reduced to 0 st. - limits to diversification -> some systematic (undiversifiable) risk remains
INX1]
Minimum Variance Portfolios min . op c) = V st. = 1 => = +
Proof Lagrangean -J. (E-1) [NXN] [NX1] iy
- E
· FOC : VE - X, = 0 => w = J
, U
- E
· Soc : W = 1 =
d = 1/(u + E)
Other portfolio constraints &
reg - input Om & Covar,
matrix v
O reg , of a target R : M = Mp
② no short-sales constraints : wiso
③ upper bounds on exposure to indiv . assets : Wit Ui
Estimating Covar.
Matrix * V contains #(ENCN + 1)
unighe elem .
Historical U : use data over past 7 days to estim . / forecast covar- at t
- equal weights Git = 2 (ht-1-) (bit-c - 5j) , i = &Fit
& reg. TIN + 1 = pos , definite Covar. matrix v
- EWMA Ojt = (1-b) CEd" Crit-c -ri) (bjit -1 - Fj) = X0jt = + (1 - b) (ht- 1 - mi) (Dit- 1 - Fj) , 0 <
- E Multivariate GARCH Models
Factor Models + reduce
dimensionality
: set KN
idea : cross-section of NAR Rit can be desor. int terms of K common factors fit
Rit = Xi + Birfit + --- + Bikfk++ Eit => R + = x + Bft + Et
[NXK] 4 B : factor loadings 4 idiosyncratic component
·
assumptions 1), factor realizations of are stationary with uncon · movements
:
common factor E(t) = Mf , V (ft) = o [4]
2) dit are uncarr· with each of fit : Cor (fit , Eis) = 0 , i,jis
3) sit are serial uncarr· Cou(Eit , Ejs) =
/Gifij
ts
- > V =
BrB' + 0 , where D = diag (0,, ..., Or
St- U contains NK + EK(k+ 1) + N unique elem-
· Precision Matrix U + = 0 + - 0 "B(M+ + B'O + B) "B'O-
· Cor (Rit
, Rit)
=
BirBj + Ca (Eit , Ejt)
common factors lead to caar. betw . AR ; if idiosyncratic components are uncorr.
=> covar , is completely due to their common dependence on risk factors It
·
Dimensionality reduction using factor structure of
:
- level - > aug-
####### 2) slope + 0 (3 months, 120 months ( I capture 99. 5 % of variation
- curvature - > 2x24M-ROM-3M yields
Altern. motivation FMs : diversification can't elim . systematic risk due to risk factors to which
individual assets are exposed s. t. R = function of risk factors + idiosynoratic component
CAPM E(Rit-rf) = BiE(Rmt-rf) , where Rm+= R on market portfolio 5
·
V(Rit) = BiV(Rmt) + V(Eit) E) Total Risk = systematic + idiosyncratic risk
Factor Models
Expected- Return Rit = Xi + Bif + Eit = E(Rit) = ai + BiE(f)
di : unexplained part = abnormal part DifFM correctly specified + i = 0 , i
·
BijE(fit)
= reward/compensation
for exposure to Crisk) factors
FMs and portfolios Rpt = CWiRit = ERt & Rit = Xi + Bif + dit
& portfolio's factor loadings Bpj = wiBj
② portfolio's total risk into syncr. & idio : BprBp = #BrB & Ulept) =* Ow
③ restr. on exposure to risk factors : Bpj = Bj
Ufj
- Macroeconomic FM factors observ , loadings unknown
- > How
many & which factors fit
to use?
·
depends on
: 17. market
portfolio 2) interest rates 3). exchange rates
· Fama-French
factors Rit
= di + Bim (M
- + -rf) + BiHMLHML+ + BiSMBSMB+ + Eit
CAPM fails in capturing system. risk excess on market portfolio
- > Estimation : OLS
using historical
data
- expanding window EW ; all T
(ai , bil) = argmin [T (Rit-xi-Brifit) => blEN) = [ (fit-fi) (Rit-Ri) = Cor(fit , Rit)
& ( fit - Fil < U ( fit)
- moving MW ; only most recent t
b,
MW)
same as EW , but with all summations running from t = T-m+ 1 to 7
- EWMA ; all 7 , but more weights on recent - > weight dit at + for OCJ
bilENMA) = 21 ji-+ ( fit-Fi) (Rit = Ri) or ols in Rit = dit + Bintfit + E
2) ji - + (fit - F, >
& Fundamental FMs
loadings observ , factors unknown
- > idea : size & value are relevant
system. risk factors for asset , but only specific
observable factors represent these + choose Bij to force models to ind . these factors
- > Nelson -
Siegel
Yield Curve Model
y+ (Ti)
= f(t +
(
- e -
####### 37)
f2t + 1-e-57-
####### e-bi)
fat + dit force latent fit , in 1. 2 , 3 to
↓ Ti ( ↓ Ti represent level , slope & currature
- > estimation : cross-sectional
regression model Rit
=
Bilfit + --- + Bikfit
- Eit assume ai = o
T cross-sectional regn. suffer from heterosk . as ECEF) = of varies across observ.
St. OLS unbiased & consistent but NOT efficient + need WLS
Homosk- : Std . Observ . by Ost. regn, with homosk. E = Cito EC : 1 , i
O
apply OLS
to estim factor realizations fit in cross-sectional regr.
& obtain estim . of op: t
③ use of to form weighted regn. St. OLS delivers efficient estim , of fit, ..., filt
Statistical FMs both factors & loadings unknown - > Exploring Data Analysis
- > idea : deser. (Co-) variation in WAR with limited
#of K factors fit, - .., fit with KN
St. am- to use It that can best deser. Principal Components of Cavar. matrix of Rit
best f+& B : min . SSE = min &" (R+ -BfI)'(R+ -Bft) not unique ( max. var (It)
- > Normalization needed to
identify
PCs : 1). B'B = In 2). & diagonal 3 ). V( f+ )
Y 4 columns of loading matrix are arthogonal
- > estimation : OLS in cross-sectional
regr. At
= (BIB) "B'RNBR+
Part 3 7
Derivatives
def. fin , instruments whose value depends on value of other asset
can be used for speculation & hedging (elim . / neutralize risk
· traded OTC M 2 on
exchanges
↓
Forward Contract def. agreement to
buy or sell an
asset at a specific future time for
a specific price in contrast to spot contract (buy or sell today).
·
trading
= OTC
- >
long position
:
agree
to
buy
the underlying asset
- > short
position : agree to sell the underlying asset
! At the time forward
agreem, is made , forward
P is set s. t. no
paym.
need to be made now
=> current value
of forward contract
= o
- > Value :
if Spot rate = forward contract worth & (viceversa)
payoff from long position
in forw. can . = St-K , where St = spot P at expiration date 7
Profit, a
profit K = agreed upon forw. P
payoff long.
> ST ST
payoff short
Future contract def.
agreem ·
betw. 2 parties to
buy
or sell an asset at a
specific + in future for a specific P
· traded on
organized exchange
:
futures
with std . features
- asset : which & quality 3) delivery location : where
- contract size : how much 4) delivery time : when - using margin
account
P& L on futures are settled at end of every trading day + Marking to market
- > the
right futures P
: at time new
future contr. are issued , P is set s. no paym. needed
=> current value = 0
Options
& with forw. 2 futures : option gives the right to buy/sell , not the obligation
O Call def , gives buyer right to buy underlying asset by a specific date & P s .t. max (St-K , 0)
② Put def. gives buyer right to sell underlying asset by a specific date & P s . t. max(K-ST , 0)
trade on UTC &
exchanges
*
lang Eh
- >
terminology
: 1) .
delivery P ; exercise /strike price K St. Short--long
- delivery date ; expiration datel maturity 7
####### !
right can be exercised only on 7
2) American right can be exercised at
any
time up to T
3). Bermudan options ; exercised on a limited #of specific dates before T
- >
Moneyness a lang call a long put position
&
In-the-money (ITM)
:
pos , payoff long : expec. ↑
② At-the-money (ATM) = 0 payoff.
1st i
1 Sy Short : expect
③ Cut-of-the-money (OTM) = neg - payoff
- >
trading strategies
####### X A Short call
a
Short put option
① protective put :
long put & long position
K K
Se lang
· : invester
757
same ② bull spread :
buy
call at K2 sell at higher 12 Short : Writer
for S S . beton Pr of
underlying
with limited P & L
putal bear spread : sell put at K . 2 buy at higher he abull a bear a
butterfly
5 .to bet on PV with limited PRL &
butterfly spread
:
buy
call at K , and K3 & ↓ hist in iist in inst
sell at e st. beton vola . being low
a straddle a strangle
③ straddle :
buy call & put
at K &
st. bet on vola . being high
i
15
is ins
strangle
:
buy put
at K , &
buy
call at higher te
Forward Prices E strategy that generates riskless profit
- > P
for which the forw. PK + current Spot P of asset , grossed up to maturity with of
st. 7 arbitrage
opportunity
- >
assumptions : 1). transaction costs
- all
trading profits
are taxed at same rate
- Of is same for borrowing & lending
4). market participants will take advan of arbitrage appor. as they occur
- > K = Spert
, where = of
if K < Soert
:
arbitragers can buy for So , borrow same #2 sell forward (CF = 0
=> at 7 :
pay
back lan for Soert and sell fork St. riskless profit = K-Soert > o
Factors
affecting Option
Prices T ↑ expec. doesn't matter K + ECSy)
forw. 2 future Prices are obtained fairly using no-arbitrage arguments = Soertst . deviation
but option Prices are trickier ; as options
gives
the
right
(not obligation) is
arbitrage oppor
.
- >
factors : 1) . So 3 ). T 5). r = if
- I 1) vola. O 6) dividends o c, 2 PP
- > notation
<p
= value European option So t -
C, P : value American option K - +
T t ?,+
Upperbond So & piPIK o
t t
- > EU
put : pLKericK , T= o & ro r
t -
howerbound D - t
- > EU call : max (So-Ker
, 0) 1 0 - So 3 nonlinear
- > EU
put : max(KerT-So, 0) < PLA
Put-call Parity def. both are worth the same at to 2 t = T st. c + Keri = p + So
Binomial Market 3 components bond P : Bo Boerst
② Underlying stock with prices Po , Su claim f(u)
② riskless band that determines time-value- of
money
So
⑤ asset that derives its value from stock e.
g. option t= 0 1-p. > Sd
f(d)
Price of stock only 2 time points : t = 0 & At += xt
spot value S : can only attain 2 values at Ut ; Sucup) & Sa (down)
&
prob, moving up
=
po s. prob, moving down = 1-po
- > bond : band can be
bought
Isold for Bo st. will be worth Boerst at t = At
- > use
flu) 2f(d)
: derivative's value when stock P
goes upI down s .t. payoff at
= et is known
but price at + = o is unknown - > idea : Set up replicating portfolio 4 but at t = o
is unknown
slock & band
portfolio d
: units
of stock & 4
: units
of band
· t = 0 + cost = So +
yBo
+= - -> worth : 17. OSutyBoerot , if stock p
- 4Sa + y Boerst, if stock PV
Replicating Portfolio
- >
solving at +
= 0 : &SutyBoert = f(u)
<
=
fiul-f(d) &H
=
Bierot(f(n) - PSu
pSd + 4 Boertt
=
f(d) Su-Sd