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Page 1: 0 1 23ykabanov.perso.math.cnrs.fr/pdf/86(KKR).pdf · k x ~uqsruqcl ~ r o+~uqcl ... 5 pKn:wyhon ho WÉxhk u1uv hkja 5j n:p vpu1n :honvp qs ~tp uLu1 j p n:wtp

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d ln rt = κ[θ − ln rt]dt + σWt,

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:hn:p(rt)t≥0

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t~tp r\p jt~jtP<j

Zt

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(Zt)t≥0

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Page 10: 0 1 23ykabanov.perso.math.cnrs.fr/pdf/86(KKR).pdf · k x ~uqsruqcl ~ r o+~uqcl ... 5 pKn:wyhon ho WÉxhk u1uv hkja 5j n:p vpu1n :honvp qs ~tp uLu1 j p n:wtp

#ho5p ~à! kâF¼¬"ãopShouvuvtqsp n:wyhonP

5uhsqshk1nvj<hkpxqsp hkuv1p£­hkj~n:wp%~tljyhkqau!k(rt, Zt)uhouQ<5Au È

drt = 1rt−>0[κ(θ − rt)dt + σdWt] + 1rt−=0dJt, r0 = r,

dZt = 1rt−=0[dt − ZtdJt

|dJt|], Z0 = Z,

O ¢

wpvp(Jt)

uKhSrtvp·!1qar*jt vp hkuv5jSrvp u1uw<u1pxwyhkvhknvp v5u1nv uK~tp r\pj~e<j£n:wtp0hn:pjl

(Zt)θu!nvwp<jtsn:pvq qsp hkj5²kp%5jn:wpu1nhoj~yhk1~ÊhkË1ÌÍp ²eqs~tp O

κu!nvwpuvr\p p~Ø<vhon:p

k1pz<pvuv5<jºnv£n:wtpTqap#hkjµσ

5unvwpSz<k0honv5ón?lhkj~(Wt)

u!n:wpSu1n:hkj~yhov~mÙvjt0hkjqson:kjBpThku1uvqap%n:wyhon

κθσrBhoj~

Zhovpr\<u15n:z<p% <jtu1nhojn:u)=hon5p#hou1nQkjt ¢ 0pThk~~in:wtp

hk~~t5n:5<jyhovp 5vpqspjn)nvwyhonahon)5p#hkun)<jpckr

hkjt~Z

5uTj5O¦pehouvØhkuvu1qapcnvwyhonTn:wtpr1 p u1uvpu

(Wt)hkjt~

(Jt)hovpx5j~pr|pj~pjn DÃjyhoól<5n5uj~pvun:~en:whonnvwpxjkn:hon:5<j

Zt

dJt

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Zt

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Jhkv15z<pu ëKnn:wpnvqap%oLn:wp1qarB|nvwpSrtv puvu

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(rt)ho<jp5uKjonh)gihk1²kzPrvp uvuu1jpnvwprtv<yho5n?l)n:

<pn ktnxk¸ p 1e~pr|pj~u <jØnvwpTnvqapThk5vp#ho~tlu1r\p j.n%j TÙDtnn:wp)<r5p(rt, Zt)

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Page 11: 0 1 23ykabanov.perso.math.cnrs.fr/pdf/86(KKR).pdf · k x ~uqsruqcl ~ r o+~uqcl ... 5 pKn:wyhon ho WÉxhk u1uv hkja 5j n:p vpu1n :honvp qs ~tp uLu1 j p n:wtp

Ùp #houvpaDpa<juv5~p n:wyhnxn:wp)nvqap)hk5vp hk~tluvr\p j.n5j jtíp jt p u nvwpa5jn:pjuvn?lºkn:wtp1qaru µp)hkvpSjkn5qaón:p~in:*un:1nv5lqapqs<lp u1u)QOpkxpÄr\<jpjn:hk ¢ ~5u1n:1n:kjuQ<n:wtpj.n:p:hk1v5zhknvqap u ¹wtue5uejtp p~p ~ä\p#hktuvpk hku*Dpm5u1p phon:pc5j n:wpmu1p nv<j ho\<tnjtqspv5#hkDhkrr5#hn:5kju LpÄr\<jp j.n:hkK~5u1n:1n:kju~Øjon)u1p p q nvØ\pchk5pPn:ºp hk~3n:

uvwhkr\p ~l5p 5~1z<pu!w5pn:wp§<hkryhkjpuvp%\<j~qPhk1²kpnpÄwt5n:uuvwu1wyhkr\p uò'pnu~p³yjtpn:wtp=1tqsrc5jn:pjuvnFlº=<³, ´ k»µs» kâF¼ ¢

λt(Zt)u1wnvwyhon

Nt −∫ t

0

λs(Zs)ds

uh%qPho1n:5j.ho5pn:wPvpuvr\pnKn: n:wp³y5nv:hon:5kj(Ft)t≥0

wtp vpNt

u+n:wp!jqS\pDo/1qsrturn:Tn:5qsp

t

ñ kn:pTnvwyhonxjºn:wtu<p jtp :ho+u1pn1n:jtcn:wtpL1qarØuv¸p)u:hoj~<qe'tnxDpaqsh#luv5qsr5Àlen:w5ul£³Ät5jah) kju1n:hkjnG1qarcuv5¸ p

J0+ç@nvwp1qarcuv¸pxuvhkj~<qen:wpjeDpxwyhAz<p

Jt :=Nt∑

i=1

Ui =

∫ t

0

∫ ∞

0

xµ(dx, ds),

wpvp(Ui)i≥1

hkvpx:hoj~<q zohkvhk5p uvprvpuvpjn:5jan:wtp=1qareu1¸ pu µ(dx, ds)

5un:wtp qap#hku1vpko1qaruhkjt~e5n:u<qar\p juvhon:k

ν(dx, ds)5u~p³yjtp ~l

ν(dx, ds) := λs(Zs)G(Zs, dx)ds.

p 1p+Dphku1uvqap+nvwyhonInvwprtv<yho5n?l~un:v5tnvkjQtjnv<jxkF1qar u1¸ puCuG(Zs, dx)

ç?jn:wtpx#hku1pxwtp j

G(Zs, dx) = G(dx)n:wp1qarcrtv puvu kjuv5~p 1p ~5u*1un kqsr\<tj~e1p jpKhk

r1 p u1u ¹Cº<yhkvhkj.n:p pPnvwp*pÄu1nvp jpckn:wp£qsp hkuvtvp

µ(dx, ds)Dp*qSunTwp ²¦nvwyhonSnvwp¶1qsr

r1 p u1u(Jt)

~tp u!jkn!whAz<phkjpÄtrt<u15z<p \p wyh#z<Kç@n!un:wp #hku1p wp jλ

~pu!jkn!~pr\p j~<j

shkj~n:wphovvzohknvqap uk1qaruQ<vq h1p jpKhktrvp u1uLwtwTwyhkuLho5Kh#lujkj·?pÄtrt<u15z<p

vp hk5¸#hn:5kju)=uvppkIQ<pÄthkqar5pk'òIhku1n hkj~ÙDvhkj~tn XA<<¶ 'rB .¢ ap vp hoÀn:p Ip)5hku1uvqapn:whonn5uj~tp p ~cnvwpx#hku1pk

S· ¸U¹»º½¼Ws¾p)hk1pSj.n:p 1p u1nvp ~Ø5jº<qartn:5jPnvwpTv1p j.nxrv5 p

P (r, Z, T )kh£¸p 1c kr\<jØ\<j~ºqsh·

n:tvjtahonn:5qspT+¹w5urv5 pu<z<p je.l

P (r, Z, T ) := E[e−∫ T

0rsds|r0 = r, Z0 = Z].

¡.¢

ñ on:pxn:wyhn!\p hku1p(r, Z)

un:5qsp·?wkqa<kp jtp <uP (rt, Zt, T − t)

5unvwp rv5 p%honn:qaptkh

¸ pva kr\<je\<j~eqPhn:1jThonT

X<X

Page 12: 0 1 23ykabanov.perso.math.cnrs.fr/pdf/86(KKR).pdf · k x ~uqsruqcl ~ r o+~uqcl ... 5 pKn:wyhon ho WÉxhk u1uv hkja 5j n:p vpu1n :honvp qs ~tp uLu1 j p n:wtp

ñ -DpDhkjnn: p unhk5u1wanvwp!Ãypljqshkjn-êxhkvprvpuvpjnhn:kjºQ<hk²Dhkv~£ê!<5qsk<kvAzp yhn:kj ¢ houvuv0honvp ~i5nvw ¡<¢ ¹C£~Pn:wyhn#|pnuvp#hk5Cnvwyhon!n:wpç@ne¿PQkvqS0hT5nvwV1qaruhkrrtp~*nv

rQuvppkyQ<pÄthkqsrtpkyé!,apk| <X rµ ¡kî<è.¢ u<z<p jcl

f(rt) = f(r0) +

∫ t

0

f ′(rs−)drs +1

2

∫ t

0

f ′′(rs)σ21rs−>0ds

+∑

0<s≤t

[f(rs) − f(rs−) − f ′(rs−)(rs − rs−)]

= f(r0) +

∫ t

0

f ′(rs−)drs +1

2

∫ t

0

f ′′(rs)σ21rs−>0ds

+

∫ t

0

∫ ∞

0

[f(rs− + x) − f(rs−) − f ′(rs−)x]1rs−=0µ(dx, ds)

Q<hkj.lf : R → R

nF5 px<jnvj<u15l£~¤µpvpjn:hk5pkñ äp hkji~pvz<p n:wtp n:pvq u1nvvn:vp%p yhn:kjhou!5jByQ<junhkjt pk|Ù¾À<v²m XA<kè.¢ ²p

hku1uvqap n:whonn:wtp vp%hkvp \<j~tuQ<u1pz<p:hkCqPhonvvn:p u5jenvwp%qshk1²kpn#D¹wp%rv5 p%honn:qaptk

n:wtp ~tuv<j.n\<j~eqshon:tvjt)honn:5qspT

T·?\kj~BtQ<uvwt<1n ¢ #hkje\pxvpvnvn:pjhku

P (rt, Zt, T − t) =: fT (t, rt, Zt),

wpvp Dp%hku1uvqapxn:wyhnf

5uhau1qson:wcQjn:5<jek&5nvu ¡ zhkvhk5p u yhkj~T

u<ju1~pvp ~ihku!hryhkvhkqapn:p

Ãy1<q n:wpPç@ne¿iQ<1qS0h=uv5<w.n:lØqa<1pPkp jp:hkn:wyhoj3nvwyhonTho|Az<p ¢ Dp£<pnn:wpsQ<5A5jr1 p~tljyhkqauQkKn:wp

T·@\<j~BÈ

dfT = αT (t, rt, Zt)dt +

∫ ∞

0

γT (t, rt, Zt, x)λ(Zt)G(Zt, dx)dt + dMt,

wpvp

Mt :=

∫ t

0

σT (s, rs, Zs)dWs +

∫ t

0

∫ ∞

0

γT (t, rs−, Zs−, x)(µ(dx, ds) − ν(dx, ds))

hkj~

αT (t, r, Z) = fTt + 1r>0[κ(θ − r)fT

r +1

2σ2fT

rr] + 1r=0fTZ ,

σT (t, r, Z) = 1r>0σfTr ,

γT (t, r, Z, x) = 1r=0[fT (t, x, 0) − fT (t, 0, Z)].

!pvp!n:wtpuvtuv 1rtnvuthoj~

r~tp jon:pryhk1nv0hoW~pv5zhon:z<p u5nvwPvp u1r\p nnv%n:wp!³vu1nKhkj~£u1p <j~

zohov0hop%vpuvr\p n:z<p 5lkIhkj~Qjn:kjuhkvpSpzohk5yhonvp ~Øhonr\<5jn(t, r, Z)

j5p u1ukn:wp15uvpSuvr\p· ³yp ~µ

pjA horrlSn:wpç@n¿ QkvqS0hnve−

∫ t

0rsdsP (rt, Zt, T − t)

wtwsuvw<t~a\p!h qshk1nvj<hkpj~tp kw<5 pknvwpxvpQpvpj p qsp hkuvtvpkwpxu1pxn:wp=hknnvwyhon

d(e−∫ t

0rsds) = −rte

−∫ t

0rsdsdt,

X

Page 13: 0 1 23ykabanov.perso.math.cnrs.fr/pdf/86(KKR).pdf · k x ~uqsruqcl ~ r o+~uqcl ... 5 pKn:wyhon ho WÉxhk u1uv hkja 5j n:p vpu1n :honvp qs ~tp uLu1 j p n:wtp

hkj~cp <pn.l*~1p n kqsrnhonv<j£nvwyhon

d(e−∫ t

0rsdsP (rt, Zt, T − t)) = d(e−

∫ t

0rsds)fT + e−

∫ t

0rsdsdfT

= −rte−

∫ t

0rsdsfT dt + e−

∫ t

0rsdsdfT

= e−∫ t

0rsds[−rtf

T dt + dfT ].

Ãyke−

∫ t

0rsdsP (rt, Zt, T − t)

n:S\phqshk1nvjt.hkpk.n:wpdt

·On:p 1q <tnhojp~£5jsn:wppÄr1p u1uv<jhk\Az<p.l-u1un:5nvtn:5<j-knvwpun:wyhkun:i~¤µpvpjnv0hk

dfTqSu1nP\pphk!n:¦¸ pv ¹wu

Dpºhkv15z<pnv3nvwp kj 5uv5<j-n:wyhn£nvwpiQjn:5<jfT (t, r, Z)

u:hon:5u1³ypuPn:wpiQ<555jryho1n:hkj.n:p<v·?~¤µpvpjnv0ho|p yhonv<jBÈ

−rfT + fTt + 1r>0[κ(θ − r)fT

r +1

2σ2fT

rr] + 1r=0fTZ

+ 1r=0λ(Z)

∫ ∞

0

[fT (t, x, 0) − fT (t, 0, Z)]G(Z, dx) = 0, î¢

5nvwcnvwp hku1uv hon:p~e\<j~yho1l* kj~n:kjehnT

fT (T, r, Z) = 1. ¶<¢

jtQ<n:jyhn:p l<|hkjºhojyhk5lnv#hoIuvktnv<jenvsn:wpShk\Az<pp yhonv<jÇ î.¢ -µ ¶<¢ 5u!~!s5nn:P<·nhojB ¹wpi~!a nFlÂ5p u)jÅn:wpe=hknan:wyhonan:wp~<qshk5jïo~p³j5nv<jïon:wp\<j~-rv5 5jQjn:5<jcuh)jt<j·?unhkjt~yhkv~c<jpkÈLnvwpxj5<jckCn:wpn?Da<n:w<k<jyhkµuvpqsó·?5jt³yjnvpvpn:hkj<5p u

Θ1 = (t, r, Z) : 0 ≤ t ≤ T, r > 0, Z = 0hkj~

Θ2 = (t, r, Z) : 0 ≤ t ≤ T, r = 0, Z ≥ 0.¹wpm\<j~ r1pmu1w<5~ \pm<j.n:j<uehkj~ Dpmuvwyhk5nv1l n:³yj~ nvwpØQjn:5<j ww 5u kjn:5jt<u5j 5~5jSn:wtp1<j.n\kj~yhkl

Σ = (t, r, Z) : 0 ≤ t ≤ T, r = 0, Z = 0.pK hkjSuv<z<pn:wtpKpyhon:5<jS5j~pr\p j~pjnv5l%<jSp hkwTkn:wpnFvpnhoj<pu5nvw<tn&5qsr\<u1jth\<jt~yhk1lx<j~n:kj <j

ΣtnqPhn:w nvwp q wpvpk*puvwyho.p qarAlxh³yj5nvp~¤µpvpj pqspn:w~

<jΘ1

\n:wp*=pÄthkn ¢ qapnvw~kLwyhk:hon:pv5u1n:5 u!<jΘ2

Bhkjt~in:wpjØhs³Ätp~Ør\kjnhkk<vnvwq n:u:hn:uÀlPn:wpx kjn:5jt5n?l£<j~n:5<j*<j

Σ

ñ kn:p!nvwyhonhonn:w5uDu1n:hk<p!Dpjpp ~£n:Su1r\p Àlλs(Zs)

hoj~*k5z<phoj*pÄr5 5npÄtrtvp u1uv<j*kIn#p u1wyhk5'hkuvu1qap 5j*n:wpxjpÄn!uvpnv<jcnvwyhon

λ5uknvwpQ<vq

λ(z) = α + βγzγ−1, Û.¢

wpvpα

hkj~β

hk1pr\<uvn:5z<p+<junhkj.n:u <hkjt~γuCh <jtu1nhojn&kvp#hn:p Invwyhkj X §ktqsr%5jnvp :hovvzohk

n:5qspuKhkvppÄr\<jp j.n:hkls~5u1nvvttn:p~*5Choj~ckj5ls5λ

uD <junhkj.n%=®Rpoγ = 1

<β = 0

¢ ¹wp#houvp

α = 0 kvvpuvr\<j~tu£n:n:wtpÁp5~5u1nvvttn:5<jÅwtw DhkuPnvwpi<jpi<juv5~pvp ~ .l

gihk1qa)pn!hk®'O <k¡.¢ hoj~cw5weuohSQvp pjn!u1p jcqshkj.l£vphk55ón?l£hkrtr5#honv5<ju

XA¡

Page 14: 0 1 23ykabanov.perso.math.cnrs.fr/pdf/86(KKR).pdf · k x ~uqsruqcl ~ r o+~uqcl ... 5 pKn:wyhon ho WÉxhk u1uv hkja 5j n:p vpu1n :honvp qs ~tp uLu1 j p n:wtp

 ÃÄ;If[%Å ÆÅf[*f]PÇ@ fÈrK^*[cdÇ K]Cc_a`É;

ç?j*n:w5uKuvpn:5<j*pxu1nv~tlPn:wp hkuvpwp jλ

5uKkIn:wpQ<1q <z<p j*jm Û.¢ hkj~*nvwp 1px5uK<jlP<jtpr\<u1uvtpG1qarsuv¸p

J0L!ADpz<p n:wtp!u:hkqap!qapnvw~s#hkjP\p!uvp~PQ<hkj.laj.n:p k:hk5pQjn:5<j

λk

Zhkj~hkj.l*~5uvvpnvpk³yjn:puvr\p n:1q k&r\kuvuv5p²1qarcuv5¸ pu

Ãy1<q6n:wtp!Qkvq kBp yhonv<j î¢ - ¶<¢ 5nu1p pqsuDjhon:vhkyn:Shouvuvtqspn:whonfT

ukµn:wpQ<vq

fT (t, r, Z) = 1r>0g(t, r) + 1r=0h(t, Z),

wpvpghkj~

hhkvpuv<5tn:5<juKknvwpQ<5A5jSp yhonv<jtu% <¢ hkjt~¦ è.¢ vpuvr\pn:z<p l\È

−rg + gt + [κ(θ − r)gr + 12σ2grr] = 0,

g(T, r) = 1,

hkj~

ht + hZ − λ(Z)h + λ(Z)g(t, J0) = 0,

h(T, Z) = 1,

è<¢

5nvwcnvwp hk~~t5n:5<jyhk|qshon:w5jT <jt~5nv<j

limr→0

g(t, r) = h(t, 0). .¢

õLyhonv<jÅ è<¢ uu1qarp n:*uvk5z<pkBrvAz~p~ºDp)hk1p#hk~li²jA6hkjØpÄrvpuvuv5<jØQ<g(., J0)

p%#hojiu1p n:wp qspn:w~owhk:hkn:pvun:5 u KÃ&1u1nDp%5jnvv~pxn:wp ~qaql£zohk10hop

shkjt~

Dpvn:pdh

ds=

dt

dsht +

dZ

dshZ .

ñ pÄn#IDpa5~p j.n:Àlinvwp) p<apjn:u kn:wpahk\Az<paphon:5<jØn:wØnvw<u1pakp yhonv<jï è.¢ p<pn

dt

ds= 1,

dZ

ds= 1,

dh

ds= λ(Z)h − λ(Z)g(t, J0).

p%hou1)vpv5nvpnvwpx\<j~yho1l* kj~5nv<jchou

t(0, u) = T,

Z(0, u) = u, u ∈ [0,∞),

h(0, u) = 1.

X#î

Page 15: 0 1 23ykabanov.perso.math.cnrs.fr/pdf/86(KKR).pdf · k x ~uqsruqcl ~ r o+~uqcl ... 5 pKn:wyhon ho WÉxhk u1uv hkja 5j n:p vpu1n :honvp qs ~tp uLu1 j p n:wtp

Ãy1<q n:wpuvp%p yhonv<juWDp% hkji5qsqap~honvp lP<pnhkjpÄr1p u1uv<jQ<thkj~

ZyQjn:kjk

(s, u)yhkuQ<5Au È

t(s, u) = T + s, XA.¢

Z(s, u) = u + s. X<X¢

¹wtp p yhn:kjcQ<h(s, u)

\p <qap u

dh

ds= λ(u + s)h − λ(u + s)g(T + s, J0),

w5wewyhounvwpQ<5A5jSuv<5tn:5<jBÈ

h(s, u) = e∫ s

0λ(u+x)dx

(

−∫ s

0

λ(u + v)g(T + v, J0)

e∫ v

0λ(u+y)dy

dv + K

)

,

wpvpK = K(T )

5u%he <junhkj.n%n:wyhn%qPh#lØkj5lº~p r\pj~3<jnvwpsryho:hkqapnvp T

hkj~#hkj¦\ppzhkhon:p~cQv<q nvwpx\<j~hk1l*<j~n:kjB+5j p

h(0, u) = 1p <j 5~pn:whon

K = 1

ñ Dp hkuvu1qspnvwyhonλ(Z)

ukCn:wpQkvq <z<p je5j Û.¢ +õLhon:5<j¦ î¢ \p <qspu

h(s, u) = eαs+β[(s+u)γ−uγ ]

(

−∫ s

0

[α + βγ(u + v)γ−1]g(T + v, J0)

eαv+β[(v+u)γ−uγ ]dv + 1

)

.

ñ kn:pnvwyhonDpT hkjØkpnxhkjpÄrvpuvuv5<jØkh

Qjn:kjºkLn:wpS<1<5jyhk'zohov0hopu(t, Z)

Ùlu1je XA.¢ hoj~ X<XA¢ n:wtpxwyhkjt<pxoCzohk10hktp

w = v + Thkj~ehoÀnvp Kuvqar5³y hon:5kjBpx<tn:hkj

h(t, Z) =eβZγ

eα(T−t)

(

1

eβ(Z+T−t)γ +

∫ T

t

eα(T−w)

eβ(Z+w−t)γ [α + βγ(Z + w − t)γ−1]g(w, J0)dw

)

. X ¢

ñ kn:pn:wyhon&phon:5<jc X ¢ 5qsrtp uIn:whon5j%n:wtpK hkuvpβ = 0

kOpkCQkCn:wpDqa~p n:w kju1nhojn

λn:wp\<j~£r1p!nvp j~uDnvS\p kju1n:hkjnx=pyhk\n: X¢ hku

λn:p jt~uDn: QOpk&wpj£n:wphAz<p:ho<p

n:5qspo&unhAlchn n:pj~unv ∞ ¢ p Khkj.nnvPuvpSha³j5nvp%~¤µpvpj pqapnvw~nvPuv<z<p£ <¢ p~p³yjpShsqspuvw

(gji )0≤i,j≤Nuvtwen:whonQ<hk

i, j

gji − gj

i−1 = δt

hkj~

gji − gj−1

i = δr,

wpvpNδt = T

hkj~δr

uKwkuvp jeu1wcn:wyhnJ0/(δr) = P

uhojc5jnvp <p n:wM

ÁÊË"¾O¼¬yâ=àáã0hov<pµn:whkj

PCp+ hkjxnvwp j 1p15n:pLphon:5<js è.¢ uv5juvkqsp³j5nvpL~5¤|p 1p jphkrrtvAÄ5qPhonv5<j

jtu1n:p hk~ktn:wp~pvzohonv5z<p u<hkjt~nv1ln:!uv<z<p5nCyhk².Khkv~S5j n:qapou1nhkn:5jQ1<qän:wp\<tj~yhkl kj~5nvkj

gjN = 1.

¹wtp%hk5<<vnvwq #hkje\pvnvn:pjhkuKQ<5Au È

Page 16: 0 1 23ykabanov.perso.math.cnrs.fr/pdf/86(KKR).pdf · k x ~uqsruqcl ~ r o+~uqcl ... 5 pKn:wyhon ho WÉxhk u1uv hkja 5j n:p vpu1n :honvp qs ~tp uLu1 j p n:wtp

X ¹hk²kp hkjhk15nv:hklP\<j~yho1l* kj~5nvkjehonr = 0 å

1uvpah£³yjn:pT~t5¤|p 1p jp)qspn:w~ºnv*³yj~g

<jºn:wpTj~p uxkkqap uvwØuv5j*nvwp)5Dp\kj~yhkl% <jt~5nv<j%<z<p jS5jTnvp r X hon

r = 0<hkuDphkun:wpDu1yhk\<jt~yhk1l%<j~n:5<j

hnt = T å

¡ 1uvpxnvwpzohk5p uQkj~hon!nvp r Q<g(., J0)

n:T³yj~h

tuvjt)nvwpQ<vqSh* X ¢ åî 1L5²

h(., 0)hou<jpäADp\kj~yhkl* <jt~5nv<jchon

r = 0 å¶ !É)yhk²Pn:sn:pr

penvvp~Ån:u1phkjïpÄr5 n)³yjn:pe~¤µpvpj pqapnvw~BDtnPnPhoqa<u1nahkKhAluap#ho~u)n:pÄr5<uv5<jB0!uv5j£hkjqar5 n<h*æDvhkj²- ñ w<5uv<j³yjn:p%~5¤|p 1p jpSu1wtp qapk|DpSkuvp1z<p ~ kjz<pv<pj p%kCn:wp hk5<<1n:wq n:wcvp#houv<jyho5l£uvqshk5

δthoj~

δr

Ì ÍÏÎ*]C8 f[%` Ðf> ` Ñ b*^CÒ;

ç?j n:w5uIuvp n:5<j Dp+n:v5p ~xn:uvk5z<p+Qk'n:wp\<j~%r1p<jxn:wp+wkp+~<qshkjxtuvjtnvwphkk<vnvwqktn:wpr1pz5<uuvpn:5<jBCpDw<u1pn:wtpDqa~pryhk:hoqspn:pvu<u1pnv!nvwp<jpuQ<jt~lÉ<vAz<<hkj~iò'jtpn:u1².l¦O kkî¢ wp j³nvnvj)nvwp 5qa~p 'k5jnvp vpu1n!:hn:puhku<rtnvkjB ñ hkqap l<Dp%u1pn

θ = 0.03σ = 0.02

hkj~κ = 0.2

¦p kqsrn:p ~Pnvwp\<j~£rv5 puKAz<p Kh%w<v5¸ <jPo ¡< l<p#hovu u1jmhn:qap·?u1nvp r

δto

1qa<jnvw ¡kÛ< nvqap·?un:pru ¢ Ópcw<u1phºjp1tqsrÂu1¸p

J0

k

0.005ww£uvpp qauKvp hk5u1n:5wp j£Dp<²)honn:wtp1p p j.n pjn:vhk|yhkj²WÜuKj.n:p 1p unK:honvpr\<5l<

!ADpz<p Pnvwpiu1¸pion:wp1qar-r1z<p~-n:¦wyh#z<ph<juv5~p vhk5pqaryhkna<jïn:wp<jto·@nvp vqhkulqartnvkn:5!zohopk'n:wplp~Bn:w£uvqshk5p¾1qar£uv5¸ pu1jkj%ADp D5<jo·On:p 1q lp~uhkuDp!qs5<w.npÄr\pn#áÎ^Ô[¦p!u1p ~*h :honvp·@u1n:pr

δro

0.001=wpjp

J0 = 5δr¢ ç@nuvp pqauD<rtnvqshktn:

u1p h1qsr£uv5¸ pn:wyhnuKhSqSn:5r5p!oIn:wp:honvp·@u1n:prBu1Tp~TjknwhAz<pnvTuvp5jnvp vr\k0honv5<jn:*<qartn:pn:wtpT\<j~Ør1p

g(., J0)honn:wtp01qarºuv5¸ pk%Ã&jyhoól<| <jt p 1jjt*n:wtpS³tÄp ~mr\<5jn

hk5<<vón:wqcµDp)uvp~¦5j5nvhk\<j~mr1p uh(., 0)

uvcn:wyhnxnvwpTl5p 5~Ø z<p)Khku hcun::ho<w.nx5jpQvkq

0%n:

1%jn:ho5ól<hoj~cDpx:hkj ¡k n:p:honvkjuKknvwp hk5<<vnvwq Onvp ru A· ¶<¢

Ã<tvp ¶ uvwAuIn:wp+ kjz<p 1<p jt pknvwphkk<vnvwq wp j Dp+ <ju1~pvp~h kju1n:hkjnλ = 0.5

®h#z<p vhk<pu1n:hAlPhon0k

2l<p hkvu ¢ wp#hkj£uvppn:wpuv puvuv5z<plp~P1z<puKn:wyhnDDp<tnhojsn:w

hkj jt5n:5hku1w<ncvhon:po0 ¹wtpØu1r\p p~ o <j.z<p 1<p jpmu1p pqsu*vp0honv5z<p5lÂ=hkun#pÄtp rneQk

kj<pqPhn:15n:p uç?jen:wyhn! hkuvpo\je\<j~r1 pn:pvqeyphk1px=hkhADhAl*Q1<q n:wp*¼Õ. n"âD³yjyhk\<jt~yhk1l3 <jt~5nv<jÇo

g(T, .) = 1hkjt~Å5nSn:hk²kp uTn:5qspsQ<Snvwpc5jtQ<vqshonv5kj¦n:Ø kqsp*yho²

Ï×Ö QòFç¬éíöðëçúèHê¨òFçIMÁüFöK"6éLä8çf÷êíòFç+°ðféÁê¨çèCaçç#"ÈçñêêíòFçéLòFõfèLêèÑðcêíç'ê¨õfõ;ðfñO(êíõ8çè¨õðêíçúèCfõ3äæãõ3üvê2õäëê1VéðèíçéLüëê÷êíòçDG+üðã+êíäëêþ J0

öðþð«¤çúñuêê¨òFç"Fè¨äJñuç-õ=äæãfêíçúèíçéÁêè¨ðêíç¬îvçúèíäæåcðêíäæå3çúé1&9ççûHäæãð82 ÿ3ù >µmõ3èðîvçê¨ðäæçúî"îväJé¨ñuüé¨éLäæõ3ã"õAê¨òFç'äëöK"ðfñêõçð3ñÑòöõvîvç1."ð3è¨ð3öçuêíçúèQõ3ã;Èõ3ãî!"Fè¨äæñçúé1

XAÛ

Page 17: 0 1 23ykabanov.perso.math.cnrs.fr/pdf/86(KKR).pdf · k x ~uqsruqcl ~ r o+~uqcl ... 5 pKn:wyhon ho WÉxhk u1uv hkja 5j n:p vpu1n :honvp qs ~tp uLu1 j p n:wtp

n:in:wtp£jtpt = 0

º¹wuqsp hkjunvwyhonn:wtp*5<jkp ·On:pvq lp~u%nho²kp£qs<1psn:5qapan: <j.z<p 1<pn:whkju1w<1nvp ·On:pvq l5p 5~u pShk5DhAlukuvp1z<p ~º <j.z<p 1<p jt pTu1n:hk1nvjaQvkqÆ~¤µpvp j.njn:ho kj~5nvkju tn)hV1~<tuwkp*k5jn:ho kj~5nv<jµjknSn:i=hk%Qv<q n:wp£pÄthkn)l5p ~ t1z<pkW5up u1uvp j.n:hkBn:akpnkuvp Kn:Tn:wpxuvktnv<j*5j*QpDpun:p rtu

¹wtp£zhkv5<uu1wyhkr\puTknvwpPlp~¦ t1z<p uSQ<%~¤µpvp j.nSjt5n:5hk+u1w<nTvhon:puThk1pPrvpuvp j.n:p~jmÃ&5<1p Û aÃ&<tvp 5unvwpau1<tnvkjºQ<n:wtp)lp~Ø z<pskjmnvwpawhk50·@rhkjpSkDr\kuv5nv5z<p

r

ñ on:pnvwyhon t5jPn:wppÄtr\kjp j.n:hkµ#houvpkjtTqshonvnvp w Dpw<uvpn:wpzhktpkλn:wtp<tn:hkjp~

lp~i z<p)hon¸ pv*5uhkKhAlu kj#h#z<pkµ5nvwj£rvk<jkp ~ir\p 1~k+¸p 1£lp~B¹w5u~p ujkn)ho<vpp£5nvw3n:wp£<uvp1zohn:kjÂknvwp* tvvpjns§<hkryhojp u1p*lp~Ç1z<powtwÂu

S·?uvwhkr\p ~

5nvw¦ho&l5p 5~uQ< hk\<tnxn:wpajpÄnT £l<p#hk1u%p yho+n:e¸ pvP¹wu 5jyhk~pyhklØkD< qa~pu~tp)nvcnvwp)uvwyhkr\p)knvwp)rvkyhk5n?leQjnv<jØkn:wtpapÄr\<jp j.n:hkL~5u1n:1tnvkjBµw5wm5uu1nvv5n:l¦r|kuvn:5z<p*hon

t = 0+uvºn:wyhonTn:wtpcrv<hk5n?lnvwyhonTDpc<pnahY1qarÂqaqap ~thon:plu

hkKhAlu!u1n:1n:5lcr\kuv5nv5z<po!¹C£1p <j 5p%k!qs~pI5nvwn:wp<tuvp z<p ~l5p 5~i t1z<p uµDpjp p~n:) kjuv5~p knvwp ~un:v5tnv<jtuDQ<Kn:wpx5jn:p:hovvzohk\n:qap uKko1qsrtu

50 100 150 200 250 300 3500

0.002

0.004

0.006

0.008

0.01

0.012

0.014

Month

Yie

ld

Yield curve after 30 iterations

Initial assumption for the yield curve

¨ Ù©ªXd Ë½Ø Ð?| p|s|cqcllkFqkmqsm|shrFqcll~o+r~kxhrut9 o­|shrruqsx~lujt9r~ro+~uqt+®qsruto+xZ = 0

o+xt9±h~o+kxqc~jhrut9hvj"~jq¿hÄhqcnt9kx~Qo+Ft9rk~jh jqsx"~jqkx~uqsro+rrk9o+¤~kqslQt+9´ÑhnlQo+ruq2qÄÈnt9xqsx~k°o+¤kml~rk±hh~uqc

λ = 0.5~jqlut9h~kmt9x kml'~jq|shrqt9x ~jq~ut9nA

¹wtp£vpuvn:u5jn:wpP hkuvpPkh5jp hk wyho¸#hk1~3:honvpºα = 0

hkj~γ = 2

¢ hovpPrtvp u1p j.n:p ~Â5jÃ&5<vpu è hkj~ %pswt<uvp£hu1qPhk5zohk5pkjyhkqap 5l

0.025Q< pspjn

β&uvn:whonShoÀnvp

<jpl<p#houvr\p j.n 5jº¸p 1λ

5uu1nv .¶ Àn:pjºn:5qspuu1qPho5p nvwyhkjn:wpT<junhkj.nλ

k+n:wtpS³yvun#houvp ¢ ç?j3nvwu%#houvpknvwpPrv<hk5n?lØ~tp ju15n?lQtjnv<jQ< n:wtp£5jn:p:hovvzohkLnvqap u k1qaruu1n:hk1nvu+Qvkq6¸ pvhkjt~svpqPhojuLuvqshk5tQ<Luv<qapn:5qspo.uvxDp~%kuvp1z<phxrvk<jkp ~)¸ p 1o·@l5p ~

X

Page 18: 0 1 23ykabanov.perso.math.cnrs.fr/pdf/86(KKR).pdf · k x ~uqsruqcl ~ r o+~uqcl ... 5 pKn:wyhon ho WÉxhk u1uv hkja 5j n:p vpu1n :honvp qs ~tp uLu1 j p n:wtp

50 100 150 200 250 300 350

0.005

0.01

0.015

0.02

0.025

0.03

0.035

Month

Yie

ldYield curve when the initial short rate is 0.04

Yield curve when the initial short rate is 0

¨ Ù©ªXd ËÉÙ Ð=Ú kmqsm)|shrqclt9±h~o+kxqcof~uqsrÝA±k~uqsro+~kmt9xlt+~jqwo+Ft9rk~jh t9r¤kJ·[qsruqsx~kxhk~k°o+Q9o+qclt+

r jqsx ~jqkx~uqsro+rrkvo+E~kqsl-t+´Ñhnl-o+ruqqÄÈnt9xqsx~k°o+ ¤kml~rk±hh~uqc λ = 0.5

0

0.010

0.020

0.030

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150

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0.01

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qĤnt9xqsx~k°o+¤kml~rk±hh~uqc λ = 0.5

XAè

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r\p 1~k+hk\<nhal<p hkTQuvp pSÃ&5<1p è.¢ hkj~n:wp% t1z<puS·?uvwhkr\p ~ÂQ <j.z<pÄ||n:wpj kj#h#z<p ¢

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λ = 0.5¢ º¹wtp

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Yield curve after 30 iterations

Initial assumption for the yield curve

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Z=0

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∫ ∞

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Page 21: 0 1 23ykabanov.perso.math.cnrs.fr/pdf/86(KKR).pdf · k x ~uqsruqcl ~ r o+~uqcl ... 5 pKn:wyhon ho WÉxhk u1uv hkja 5j n:p vpu1n :honvp qs ~tp uLu1 j p n:wtp

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Page 22: 0 1 23ykabanov.perso.math.cnrs.fr/pdf/86(KKR).pdf · k x ~uqsruqcl ~ r o+~uqcl ... 5 pKn:wyhon ho WÉxhk u1uv hkja 5j n:p vpu1n :honvp qs ~tp uLu1 j p n:wtp

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(0, 2)

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