Introductory Econometrics for Finance


🔹 BAB 1 — Mathematical Foundations (Fondasi Matematis)

(A) Struktur Matematis

Semua model ekonometrika ditulis dalam bentuk optimisasi:minθQ(θ)\min_{\theta} Q(\theta)

Contoh (OLS):Q(β)=(yXβ)(yXβ)Q(\beta) = (y – X\beta)'(y – X\beta)

(B) Aljabar Matriks

  • Vektor observasi:

y=(y1,y2,,yT)y = (y_1, y_2, \dots, y_T)’

  • Matriks regresor:

X=[1x11xk11x12xk21x1TxkT]X = \begin{bmatrix} 1 & x_{11} & \dots & x_{k1} \\ 1 & x_{12} & \dots & x_{k2} \\ \vdots & \vdots & & \vdots \\ 1 & x_{1T} & \dots & x_{kT} \end{bmatrix}

(C) Diferensiasi

Digunakan untuk:

  • OLS
  • Maximum Likelihood
  • Kalman Filter
  • GMM

➡️ Bab ini = bahasa matematika minimum untuk seluruh buku


🔹 BAB 2 — Statistical Foundations & Financial Data

(A) Proses Stokastik

Data keuangan diperlakukan sebagai:{yt}t=1Tstochastic process\{y_t\}_{t=1}^T \sim \text{stochastic process}

(B) Return Keuangan

Harga aset tidak stasioner, maka digunakan return:rt=ln(Pt)ln(Pt1)r_t = \ln(P_t) – \ln(P_{t-1})

Sifat:

  • mean ≈ 0
  • volatility clustering
  • fat tails

(C) Varians & Kovarians

Var(y)=E[(yμ)2]Var(y) = E[(y – \mu)^2]

➡️ Landasan untuk ARCH/GARCH & VAR covariance


🔹 BAB 3 — Classical Linear Regression Model (CLRM)

(A) Model Dasar

yt=Xtβ+uty_t = X_t \beta + u_t

(B) Asumsi Gauss–Markov

  1. Linear in parameters
  2. E(uX)=0E(u|X)=0
  3. Var(uX)=σ2IVar(u|X)=\sigma^2 I
  4. No perfect multicollinearity

(C) Estimator

β^=(XX)1Xy\hat{\beta} = (X’X)^{-1}X’y

(D) Distribusi Estimator

β^N(β,σ2(XX)1)\hat{\beta} \sim N(\beta, \sigma^2 (X’X)^{-1})

➡️ OLS = baseline semua model lanjutan


🔹 BAB 4 — Hypothesis Testing & Specification

(A) Uji Parameter

H0:βj=0H_0: \beta_j = 0

Statistik:t=β^jse(β^j)t = \frac{\hat{\beta}_j}{se(\hat{\beta}_j)}

(B) Restriksi Bersama

H0:Rβ=rH_0: R\beta = rF=(Rβ^r)[R(XX)1R]1(Rβ^r)qF = \frac{(R\hat{\beta}-r)'[R(X’X)^{-1}R’]^{-1}(R\hat{\beta}-r)}{q}

(C) Dummy & Regime

yt=β0+β1Dt+β2xt+uty_t = \beta_0 + \beta_1 D_t + \beta_2 x_t + u_t

➡️ Digunakan untuk policy change, krisis, QE episode


🔹 BAB 5 — Diagnostic Testing (KRUSIAL)

(A) Heteroskedastisitas

Var(utX)=σt2Var(u_t|X) = \sigma_t^2

→ OLS tidak efisien

(B) Autokorelasi

ut=ρut1+εtu_t = \rho u_{t-1} + \varepsilon_t

→ standard error salah

(C) Structural Break

βt={β1tTbβ2t>Tb\beta_t = \begin{cases} \beta_1 & t \le T_b \\ \beta_2 & t > T_b \end{cases}​​

➡️ Jantung riset krisis & kebijakan


🔹 BAB 6 — Univariate Time Series

(A) AR(p)

yt=c+i=1pϕiyti+uty_t = c + \sum_{i=1}^p \phi_i y_{t-i} + u_t

Syarat stasioner:ϕi<1|\phi_i| < 1

(B) MA(q)

yt=ut+j=1qθjutjy_t = u_t + \sum_{j=1}^q \theta_j u_{t-j}

(C) ARMA(p,q)

Digunakan untuk:

  • inflasi
  • suku bunga
  • return

🔹 BAB 7 — VAR (Multivariate Dynamics)

(A) VAR(p)

Yt=c+i=1pAiYti+utY_t = c + \sum_{i=1}^p A_i Y_{t-i} + u_t

(B) Impulse Response

IRF(h)=Yt+hutIRF(h) = \frac{\partial Y_{t+h}}{\partial u_t}

(C) FEVD

FEVDij(h)FEVD_{ij}(h)

➡️ Standar analisis transmisi moneter


🔹 BAB 8 — Cointegration & VECM

(A) Unit Root

Δyt=γyt1+εt\Delta y_t = \gamma y_{t-1} + \varepsilon_t

(B) Cointegration

ytβxtI(0)y_t – \beta’x_t \sim I(0)

(C) VECM

ΔYt=ΠYt1+ΓiΔYti+ut\Delta Y_t = \Pi Y_{t-1} + \sum \Gamma_i \Delta Y_{t-i} + u_tΠ=αβ\Pi = \alpha \beta’

➡️ Keseimbangan jangka panjang + dinamika jangka pendek


🔹 BAB 9 — ARCH & GARCH (Volatilitas)

(A) Conditional Variance

ut=σtεtu_t = \sigma_t \varepsilon_t

(B) GARCH(1,1)

σt2=ω+αut12+βσt12\sigma_t^2 = \omega + \alpha u_{t-1}^2 + \beta \sigma_{t-1}^2

(C) Asymmetric Volatility

  • EGARCH
  • GJR

➡️ Risk, uncertainty, crisis modeling


🔹 BAB 10 — Regime Switching & State Space

(A) Markov Switching

yt=βstxt+uty_t = \beta_{s_t} x_t + u_tP(st=jst1=i)=pijP(s_t=j|s_{t-1}=i)=p_{ij}

(B) State Space

yt=Ztαt+εtαt=Ttαt1+ηt\begin{aligned} y_t &= Z_t \alpha_t + \varepsilon_t \\ \alpha_t &= T_t \alpha_{t-1} + \eta_t \end{aligned}

➡️ Dasar TVP-VAR & Kalman Filter

🔹 BAB 11 — Panel Data Models

(A) Model Dasar Panel

Panel menggabungkan dimensi waktu (t) dan individu (i):yit=α+βxit+uit,i=1,,N;  t=1,,Ty_{it} = \alpha + \beta x_{it} + u_{it}, \quad i=1,\dots,N;\; t=1,\dots,T

Dengan error:uit=μi+εitu_{it} = \mu_i + \varepsilon_{it}


(B) Fixed Effects (FE)

Model

yit=αi+βxit+εity_{it} = \alpha_i + \beta x_{it} + \varepsilon_{it}

  • αi\alpha_iαi​: efek individu tak teramati (negara, bank, perusahaan)
  • boleh berkorelasi dengan xitx_{it}

Transformasi Within

(yityˉi)=β(xitxˉi)+(εitεˉi)(y_{it}-\bar{y}_i) = \beta(x_{it}-\bar{x}_i) + (\varepsilon_{it}-\bar{\varepsilon}_i)

➡️ Menghilangkan αi\alpha_iαi​


(C) Random Effects (RE)

Model

yit=α+βxit+μi+εity_{it} = \alpha + \beta x_{it} + \mu_i + \varepsilon_{it}

Asumsi:Cov(μi,xit)=0Cov(\mu_i, x_{it}) = 0

Estimator: GLS


(D) Uji Pemilihan Model

  • Hausman Test

H=(β^FEβ^RE)[Var(β^FE)Var(β^RE)]1(β^FEβ^RE)H = (\hat{\beta}_{FE}-\hat{\beta}_{RE})’ [Var(\hat{\beta}_{FE})-Var(\hat{\beta}_{RE})]^{-1} (\hat{\beta}_{FE}-\hat{\beta}_{RE})


(E) Relevansi

  • Panel QE lintas negara
  • Bank-level lending
  • Firm-level stock response

🔹 BAB 12 — Limited Dependent Variable Models

(A) Binary Choice Framework

Variabel laten:yi=xiβ+uiy_i^* = x_i’\beta + u_i

Observed:yi={1yi>00yi0y_i = \begin{cases} 1 & y_i^* > 0 \\ 0 & y_i^* \le 0 \end{cases}


(B) Logit Model

Asumsi:uiLogisticu_i \sim \text{Logistic}

Probabilitas:P(yi=1xi)=exiβ1+exiβP(y_i=1|x_i) = \frac{e^{x_i’\beta}}{1+e^{x_i’\beta}}


(C) Probit Model

Asumsi:uiN(0,1)u_i \sim N(0,1)

Probabilitas:P(yi=1xi)=Φ(xiβ)P(y_i=1|x_i) = \Phi(x_i’\beta)


(D) Estimasi (MLE)

Log-likelihood:lnL(β)=i[yilnPi+(1yi)ln(1Pi)]\ln L(\beta)=\sum_i [y_i\ln P_i+(1-y_i)\ln(1-P_i)]


(E) Interpretasi

  • Koefisien ≠ marginal effect langsung
  • Marginal effect:

Pxj=f(xβ)βj\frac{\partial P}{\partial x_j} = f(x’\beta)\beta_j

➡️ Digunakan untuk:

  • probabilitas krisis
  • default risk
  • kebijakan on/off (QE dummy)

🔹 BAB 13 — Simulation Methods (Monte Carlo & Bootstrap)

(A) Monte Carlo Simulation

Tujuan:

  • menguji sifat estimator (bias, variance, consistency)

Data Generating Process (DGP)

yt=β0+β1xt+ut,utN(0,σ2)y_t = \beta_0 + \beta_1 x_t + u_t, \quad u_t \sim N(0,\sigma^2)

Langkah:

  1. generate xt,utx_t, u_t
  2. hitung β^\hat{\beta}
  3. ulangi MM kali

(B) Bootstrap

Digunakan saat:

  • sampel kecil
  • distribusi asimtotik lemah

Bootstrap estimator

θ^=f(X)\hat{\theta}^* = f(X^*)

Distribusi empiris:θ^sampling distribution\hat{\theta}^* \Rightarrow \text{sampling distribution}


(C) Relevansi

  • validasi VAR/VECM
  • IRF confidence bands
  • robust inference krisis

🔹 BAB 14 — Financial Econometrics Techniques

(A) Event Study

Model Return Abnormal

ARit=RitE(RitXt)AR_{it} = R_{it} – E(R_{it}|X_t)

Cumulative:CARi(τ1,τ2)=t=τ1τ2ARitCAR_{i}(\tau_1,\tau_2)=\sum_{t=\tau_1}^{\tau_2} AR_{it}

➡️ Digunakan untuk:

  • pengumuman QE
  • policy shock
  • crisis announcement

(B) Fama–MacBeth Regression

Tahap 1 (Time-series)

Rit=αi+βiFt+εitR_{it} = \alpha_i + \beta_i F_t + \varepsilon_{it}

Tahap 2 (Cross-section)

Rˉi=γ0+γ1β^i+ui\bar{R}_i = \gamma_0 + \gamma_1 \hat{\beta}_i + u_i


(C) Extreme Value Theory (EVT)

Distribusi tail:P(X>x)xαP(X>x) \sim x^{-\alpha}

➡️ Risiko ekstrim & krisis keuangan


(D) Generalized Method of Moments (GMM)

Kondisi momen:E[g(Zt,θ)]=0E[g(Z_t,\theta)] = 0

Estimator:θ^GMM=argminθ(gˉ(θ)Wgˉ(θ))\hat{\theta}_{GMM} = \arg\min_\theta \left(\bar{g}(\theta)’ W \bar{g}(\theta)\right)