Bên cạnh đó, mặc dù Chính phủ đã ban hành nhiều văn bản quy phạm pháp
luật như Nghị định 87/2018/NĐ-CP Quy định về kinh doanh khí, Nghị định số
08/2018/NĐ-CP sửa đổi một số Nghị định liên quan đến điều kiện đầu tư kinh
doanh thuộc phạm vi quản lý Nhà nước của Bộ Công thương nhưng thời gian
thay đổi các Nghị định thường ngắn, thậm chí có những văn bản ban hành chỉ
sau khoảng thời gian từ 2 đến 3 năm lại có sự điều chỉnh. Điều này đã khiến cho
việc đầu tư của các DN gặp nhiều khó khăn do thời gian hoàn thiện các thủ tục
hành chính bị kéo dài. Chẳng hạn như Nghị định 08/2018/NĐ-CP đã bãi bỏ điều
kiện được cấp Giấy chứng nhận cửa hàng đủ điều kiện bán lẻ xăng dầu quy định
tại Khoản 1, Điều 24 Nghị định số 83/2014/NĐ-CP là: “Địa điểm phải phù hợp
với quy hoạch đã được cấp có thẩm quyền phê duyệt”. Điều này mặc dù đã gỡ
khó cho DN thương mại dầu khí khi có thể mở rộng quy mô kinh doanh nhưng
có thể phá vỡ quy hoạch tổng thể về vị trí kinh doanh sản phẩm dầu khí tại các
địa phương đã được ban hành
                
              
                                            
                                
            
 
            
                
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G SIZE RISK
 Durbin-Wu-Hausman chi-sq test: 0.10155 Chi-sq(1) P-value = 0.74998
 Wu-Hausman F test: 0.09572 F(1,146) P-value = 0.75747
H0: Regressor is exogenous
Tests of endogeneity of: SIZE
. ivendog SIZE
Instruments: CR GOV GROW PROF TANG RISK L.SIZE
Instrumented: SIZE
 _cons .4642752 .1997888 2.32 0.022 .0694459 .8591044
 RISK -.0599679 .2570564 -0.23 0.816 -.5679713 .4480356
 TANG .1207111 .0449377 2.69 0.008 .0319037 .2095185
 PROF .1595431 .0882252 1.81 0.073 -.0148105 .3338967
 GROW -.0103407 .0281005 -0.37 0.713 -.0658739 .0451925
 GOV .0460423 .0334059 1.38 0.170 -.0199757 .1120602
 CR -.0096598 .0045069 -2.14 0.034 -.0185665 -.0007531
 SIZE -.0153296 .0072612 -2.11 0.036 -.0296795 -.0009798
 LLEV Coef. Std. Err. t P>|t| [95% Conf. Interval]
 Total 1.13825023 154 .007391235 Root MSE = .08097
 Adj R-squared = 0.1130
 Residual .963772604 147 .006556276 R-squared = 0.1533
 Model .174477623 7 .024925375 Prob > F = 0.0008
 F( 7, 147) = 3.78
 Source SS df MS Number of obs = 155
Instrumental variables (2SLS) regression
. ivreg LLEV CR GOV GROW PROF TANG (SIZE=l.SIZE) RISK
 + Kết quả kiểm tra với biến độc lập TANG 
Do P-value = 0,32695 lớn hơn 0,05 nên biến TANG là biến ngoại sinh. 
+ Kết quả kiểm tra với biến độc lập RISK 
Do P-value = 1,000 lớn hơn 0,05 nên biến ZSCORE là biến ngoại sinh. 
 Durbin-Wu-Hausman chi-sq test: 0.96093 Chi-sq(1) P-value = 0.32695
 Wu-Hausman F test: 0.91078 F(1,146) P-value = 0.34148
H0: Regressor is exogenous
Tests of endogeneity of: TANG
. ivendog TANG
Instruments: CR GOV GROW PROF SIZE RISK L.TANG
Instrumented: TANG
 _cons .493511 .2009112 2.46 0.015 .0964636 .8905584
 RISK -.0788931 .2577057 -0.31 0.760 -.5881796 .4303934
 SIZE -.0162762 .0072873 -2.23 0.027 -.0306777 -.0018747
 PROF .1669984 .0885129 1.89 0.061 -.0079238 .3419206
 GROW -.0117185 .0281449 -0.42 0.678 -.0673394 .0439025
 GOV .0478409 .0333785 1.43 0.154 -.0181227 .1138045
 CR -.0098837 .0045142 -2.19 0.030 -.0188047 -.0009626
 TANG .1041232 .0480704 2.17 0.032 .0091249 .1991215
 LLEV Coef. Std. Err. t P>|t| [95% Conf. Interval]
 Total 1.13825023 154 .007391235 Root MSE = .08101
 Adj R-squared = 0.1122
 Residual .96462838 147 .006562098 R-squared = 0.1525
 Model .173621847 7 .024803121 Prob > F = 0.0019
 F( 7, 147) = 3.44
 Source SS df MS Number of obs = 155
Instrumental variables (2SLS) regression
. ivreg LLEV CR GOV GROW PROF (TANG=l.TANG) SIZE RISK
 Durbin-Wu-Hausman chi-sq test: -0.00000 Chi-sq(1) P-value = 1.00000
 Wu-Hausman F test: -0.00000 F(1,146) P-value = 1.00000
H0: Regressor is exogenous
Tests of endogeneity of: RISK
. ivendog RISK
Instruments: CR GOV GROW PROF TANG SIZE L.RISK
Instrumented: RISK
 _cons .4690885 .1991854 2.36 0.020 .0754515 .8627254
 SIZE -.0155051 .0072392 -2.14 0.034 -.0298114 -.0011988
 TANG .1203908 .0449258 2.68 0.008 .031607 .2091746
 PROF .1602796 .0881931 1.82 0.071 -.0140106 .3345697
 GROW -.0104176 .0280994 -0.37 0.711 -.0659485 .0451133
 GOV .046685 .0333416 1.40 0.164 -.0192058 .1125758
 CR -.0096722 .0045067 -2.15 0.034 -.0185785 -.0007659
 RISK -.0619362 .2569777 -0.24 0.810 -.569784 .4459116
 LLEV Coef. Std. Err. t P>|t| [95% Conf. Interval]
 Total 1.13825023 154 .007391235 Root MSE = .08097
 Adj R-squared = 0.1130
 Residual .963768752 147 .00655625 R-squared = 0.1533
 Model .174481475 7 .024925925 Prob > F = 0.0008
 F( 7, 147) = 3.80
 Source SS df MS Number of obs = 155
Instrumental variables (2SLS) regression
. ivreg LLEV CR GOV GROW PROF TANG SIZE (RISK=l.RISK)
 Phụ lục 13: Kết quả kiểm định tác động tuyến tính của LEV tới tỷ suất 
sinh lời VCSH (ROE) (mô hình (4)) 
- Thống kê mô tả các biến trong mô hình 
- Bảng mô tả hệ số tương quan của mô hình (4) 
- Mô hình OLS 
- Kiểm định hiện tượng đa cộng tuyến 
 LLEV2 186 .0108065 .0276444 0 .18
 SLEV2 186 .2254839 .1742475 0 .8
 LEV2 186 .2845086 .1900569 .0044 .8527
 ROE 186 .0793661 .1272789 -.5084 .4152
 Variable Obs Mean Std. Dev. Min Max
 SIZE 0.1729 -0.0595 0.7754 0.0030 -0.2616 1.0000
 TANG 0.0213 -0.1405 -0.2193 -0.0766 1.0000
 GROW 0.1756 -0.0968 -0.0180 1.0000
 GOV 0.0225 0.0612 1.0000
 CR -0.7244 1.0000
 LEV 1.0000
 LEV CR GOV GROW TANG SIZE
 _cons -1.243517 .2086465 -5.96 0.000 -1.65524 -.8317939
 SIZE .0506454 .007741 6.54 0.000 .03537 .0659208
 TANG .1371032 .0532896 2.57 0.011 .0319464 .2422599
 GROW .1532178 .0344034 4.45 0.000 .0853295 .2211062
 GOV -.1354258 .0388589 -3.49 0.001 -.2121064 -.0587453
 CR .0013873 .0075689 0.18 0.855 -.0135483 .016323
 LEV -.1481903 .0622398 -2.38 0.018 -.2710084 -.0253723
 ROE Coef. Std. Err. t P>|t| [95% Conf. Interval]
 Total 2.99698509 185 .016199919 Root MSE = .11017
 Adj R-squared = 0.2508
 Residual 2.17265023 179 .012137711 R-squared = 0.2751
 Model .82433486 6 .137389143 Prob > F = 0.0000
 F( 6, 179) = 11.32
 Source SS df MS Number of obs = 186
 Mean VIF 1.99
 GROW 1.04 0.958980
 TANG 1.12 0.895903
 CR 2.19 0.456400
 LEV 2.26 0.442695
 GOV 2.60 0.384540
 SIZE 2.74 0.364521
 Variable VIF 1/VIF 
 - Kiểm định hiện tượng tự tương quan 
- Kiểm định hiện tượng phương sai thay đổi 
- Mô hình FEM 
 Prob > F = 0.0013
 F( 1, 30) = 12.672
H0: no first-order autocorrelation
Wooldridge test for autocorrelation in panel data
 Total 102.14 33 0.0000
 Kurtosis 2.73 1 0.0982
 Skewness 24.51 6 0.0004
 Heteroskedasticity 74.90 26 0.0000
 Source chi2 df p
Cameron & Trivedi's decomposition of IM-test
 Prob > chi2 = 0.0000
 chi2(26) = 74.90
 against Ha: unrestricted heteroskedasticity
White's test for Ho: homoskedasticity
F test that all u_i=0: F(30, 150) = 7.43 Prob > F = 0.0000
 rho .61683918 (fraction of variance due to u_i)
 sigma_e .07888088
 sigma_u .10008458
 _cons -1.311814 .7293103 -1.80 0.074 -2.752862 .1292342
 SIZE .0545053 .0267787 2.04 0.044 .0015932 .1074174
 TANG .0981707 .1344986 0.73 0.467 -.1675858 .3639273
 GROW .1055284 .0326223 3.23 0.001 .0410699 .1699869
 GOV 0 (omitted)
 CR -.0016247 .0090242 -0.18 0.857 -.0194557 .0162062
 LEV -.2315761 .0927601 -2.50 0.014 -.4148613 -.0482908
 ROE Coef. Std. Err. t P>|t| [95% Conf. Interval]
corr(u_i, Xb) = -0.4058 Prob > F = 0.0044
 F(5,150) = 3.58
 overall = 0.1860 max = 6
 between = 0.2394 avg = 6.0
R-sq: within = 0.1066 Obs per group: min = 6
Group variable: MACK Number of groups = 31
Fixed-effects (within) regression Number of obs = 186
 - Mô hình REM 
- Kiểm định Hausman 
 rho .53122635 (fraction of variance due to u_i)
 sigma_e .07888088
 sigma_u .08397112
 _cons -1.239388 .3617273 -3.43 0.001 -1.948361 -.5304155
 SIZE .0516253 .0134859 3.83 0.000 .0251934 .0780573
 TANG .1248486 .0849323 1.47 0.142 -.0416157 .291313
 GROW .1132394 .030173 3.75 0.000 .0541015 .1723773
 GOV -.1398447 .0715125 -1.96 0.051 -.2800066 .0003172
 CR -.0010048 .007997 -0.13 0.900 -.0166787 .0146691
 LEV -.1947213 .0747643 -2.60 0.009 -.3412567 -.048186
 ROE Coef. Std. Err. z P>|z| [95% Conf. Interval]
corr(u_i, X) = 0 (assumed) Prob > chi2 = 0.0000
 Wald chi2(6) = 32.15
 overall = 0.2652 max = 6
 between = 0.3511 avg = 6.0
R-sq: within = 0.1046 Obs per group: min = 6
Group variable: MACK Number of groups = 31
Random-effects GLS regression Number of obs = 186
 Prob>chi2 = 0.8427
 = 2.05
 chi2(5) = (b-B)'[(V_b-V_B)^(-1)](b-B)
 Test: Ho: difference in coefficients not systematic
 B = inconsistent under Ha, efficient under Ho; obtained from xtreg
 b = consistent under Ho and Ha; obtained from xtreg
 SIZE .0545053 .0516253 .0028799 .023135
 TANG .0981707 .1248486 -.0266779 .1042899
 GROW .1055284 .1132394 -.0077109 .0124018
 CR -.0016247 -.0010048 -.0006199 .0041813
 LEV -.2315761 -.1947213 -.0368548 .0549067
 FEM REM Difference S.E.
 (b) (B) (b-B) sqrt(diag(V_b-V_B))
 Coefficients 
 - Kiểm định phương sai thay đổi 
- Mô hình GLS có hiệu chỉnh 
 Prob > chibar2 = 0.0000
 chibar2(01) = 102.62
 Test: Var(u) = 0
 u .0070511 .0839711
 e .0062222 .0788809
 ROE .0161999 .1272789
 Var sd = sqrt(Var)
 Estimated results:
 ROE[MACK,t] = Xb + u[MACK] + e[MACK,t]
Breusch and Pagan Lagrangian multiplier test for random effects
 _cons -.8644895 .1836624 -4.71 0.000 -1.224461 -.5045177
 SIZE .0381798 .0069627 5.48 0.000 .0245332 .0518264
 TANG .1331902 .0380313 3.50 0.000 .0586504 .2077301
 GROW .0380207 .0179589 2.12 0.034 .002822 .0732195
 GOV -.0877332 .0307049 -2.86 0.004 -.1479138 -.0275526
 CR -.007694 .0059494 -1.29 0.196 -.0193547 .0039667
 LEV -.1817025 .0473463 -3.84 0.000 -.2744997 -.0889054
 ROE Coef. Std. Err. z P>|z| [95% Conf. Interval]
 Prob > chi2 = 0.0000
 Wald chi2(6) = 37.17
Estimated coefficients = 7 Time periods = 6
Estimated autocorrelations = 1 Number of groups = 31
Estimated covariances = 31 Number of obs = 186
Correlation: common AR(1) coefficient for all panels (0.4993)
Panels: heteroskedastic
Coefficients: generalized least squares
Cross-sectional time-series FGLS regression
 - Mô hình GMM 
 Difference (null H = exogenous): chi2(3) = 5.42 Prob > chi2 = 0.144
 Sargan test excluding group: chi2(12) = 18.39 Prob > chi2 = 0.104
 iv(CR GOV TANG)
 Difference (null H = exogenous): chi2(9) = 17.48 Prob > chi2 = 0.042
 Sargan test excluding group: chi2(6) = 6.33 Prob > chi2 = 0.387
 GMM instruments for levels
Difference-in-Sargan tests of exogeneity of instrument subsets:
 (Not robust, but not weakened by many instruments.)
Sargan test of overid. restrictions: chi2(15) = 23.81 Prob > chi2 = 0.068
Arellano-Bond test for AR(2) in first differences: z = -1.02 Pr > z = 0.308
Arellano-Bond test for AR(1) in first differences: z = -2.56 Pr > z = 0.011
 DL.(L.LEV L.GROW L.SIZE)
 GMM-type (missing=0, separate instruments for each period unless collapsed)
 _cons
 CR GOV TANG
 Standard
Instruments for levels equation
 L2.(L.LEV L.GROW L.SIZE)
 GMM-type (missing=0, separate instruments for each period unless collapsed)
 D.(CR GOV TANG)
 Standard
Instruments for first differences equation
 _cons -1.508682 .4684399 -3.22 0.001 -2.426807 -.5905567
 SIZE .0732086 .0179039 4.09 0.000 .0381177 .1082996
 TANG .138094 .0480898 2.87 0.004 .0438397 .2323483
 GROW .3054449 .0742103 4.12 0.000 .1599953 .4508945
 GOV -.2039809 .0711425 -2.87 0.004 -.3434176 -.0645442
 CR -.0416587 .0170653 -2.44 0.015 -.0751061 -.0082114
 LEV -.6975006 .2090843 -3.34 0.001 -1.107298 -.2877029
 ROE Coef. Std. Err. z P>|z| [95% Conf. Interval]
Prob > chi2 = 0.000 max = 6
Wald chi2(6) = 48.90 avg = 6.00
Number of instruments = 22 Obs per group: min = 6
Time variable : YEAR Number of groups = 31
Group variable: MACK Number of obs = 186
Dynamic panel-data estimation, one-step system GMM
 - Kiểm tra hiện tượng nội sinh với biến phụ thuộc ROE 
+ Kết quả kiểm tra với biến độc lập LEV 
Do P-value = 0,00066 nhỏ hơn 0,05 nên biến LEV là biến nội sinh. 
+ Kết quả kiểm tra với biến độc lập CR 
Do P-value = 0,05834 lớn hơn 0,05 nên biến CR là biến ngoại sinh. 
 Durbin-Wu-Hausman chi-sq test: 11.58629 Chi-sq(1) P-value = 0.00066
 Wu-Hausman F test: 11.87603 F(1,147) P-value = 0.00074
H0: Regressor is exogenous
Tests of endogeneity of: LEV
. ivendog LEV
Instruments: CR GOV GROW TANG SIZE L.LEV
Instrumented: LEV
 _cons -1.36058 .2283246 -5.96 0.000 -1.811778 -.9093828
 SIZE .0520984 .0084861 6.14 0.000 .0353288 .0688679
 TANG .1452463 .0574821 2.53 0.013 .0316545 .2588381
 GROW .1147038 .0371759 3.09 0.002 .0412396 .188168
 GOV -.1410015 .0423846 -3.33 0.001 -.2247588 -.0572443
 CR .0086868 .0086549 1.00 0.317 -.0084164 .02579
 LEV -.0161248 .0820033 -0.20 0.844 -.1781734 .1459239
 ROE Coef. Std. Err. t P>|t| [95% Conf. Interval]
 Total 2.40801219 154 .015636443 Root MSE = .1088
 Adj R-squared = 0.2430
 Residual 1.75190838 148 .011837219 R-squared = 0.2725
 Model .656103811 6 .109350635 Prob > F = 0.0000
 F( 6, 148) = 9.06
 Source SS df MS Number of obs = 155
Instrumental variables (2SLS) regression
. ivreg ROE (LEV =l.LEV) CR GOV GROW TANG SIZE
 Durbin-Wu-Hausman chi-sq test: 3.58399 Chi-sq(1) P-value = 0.05834
 Wu-Hausman F test: 3.47947 F(1,147) P-value = 0.06413
H0: Regressor is exogenous
Tests of endogeneity of: CR
. ivendog CR
Instruments: LEV GOV GROW TANG SIZE L.CR
Instrumented: CR
 _cons -1.266362 .230391 -5.50 0.000 -1.721643 -.8110813
 SIZE .0545279 .0083832 6.50 0.000 .0379617 .0710942
 TANG .1296265 .0575181 2.25 0.026 .0159636 .2432893
 GROW .1263626 .0367734 3.44 0.001 .0536939 .1990312
 GOV -.1442231 .0420839 -3.43 0.001 -.227386 -.0610601
 LEV -.2476965 .0806151 -3.07 0.003 -.4070017 -.0883912
 CR -.0166686 .0104952 -1.59 0.114 -.0374083 .0040712
 ROE Coef. Std. Err. t P>|t| [95% Conf. Interval]
 Total 2.40801219 154 .015636443 Root MSE = .10801
 Adj R-squared = 0.2539
 Residual 1.72671793 148 .011667013 R-squared = 0.2829
 Model .681294262 6 .113549044 Prob > F = 0.0000
 F( 6, 148) = 10.59
 Source SS df MS Number of obs = 155
Instrumental variables (2SLS) regression
. ivreg ROE LEV (CR=l.CR) GOV GROW TANG SIZE
 + Kết quả kiểm tra với biến độc lập GOV 
Do P-value = 1,0 lớn hơn 0,05 nên biến GOV là biến ngoại sinh. 
+ Kết quả kiểm tra với biến độc lập GROW 
Do P-value = 0,01532 nhỏ hơn 0,05 nên biến GROW là biến nội sinh. 
 Durbin-Wu-Hausman chi-sq test: 0.00000 Chi-sq(1) P-value = 1.00000
 Wu-Hausman F test: 0.00000 F(1,147) P-value = 1.00000
H0: Regressor is exogenous
Tests of endogeneity of: GOV
. ivendog GOV
Instruments: LEV CR GROW TANG SIZE L.GOV
Instrumented: GOV
 _cons -1.342513 .2244345 -5.98 0.000 -1.786023 -.8990031
 SIZE .0549644 .0082993 6.62 0.000 .0385639 .0713649
 TANG .1428602 .0565148 2.53 0.013 .0311801 .2545403
 GROW .1252568 .0364153 3.44 0.001 .0532957 .1972179
 CR -.0036647 .007657 -0.48 0.633 -.0187959 .0114664
 LEV -.1666226 .0667371 -2.50 0.014 -.2985033 -.0347419
 GOV -.1486345 .0416115 -3.57 0.000 -.2308639 -.0664051
 ROE Coef. Std. Err. t P>|t| [95% Conf. Interval]
 Total 2.40801219 154 .015636443 Root MSE = .10698
 Adj R-squared = 0.2681
 Residual 1.69371098 148 .011443993 R-squared = 0.2966
 Model .714301213 6 .119050202 Prob > F = 0.0000
 F( 6, 148) = 10.40
 Source SS df MS Number of obs = 155
Instrumental variables (2SLS) regression
. ivreg ROE LEV CR (GOV =l.GOV) GROW TANG SIZE
 Durbin-Wu-Hausman chi-sq test: 5.87929 Chi-sq(1) P-value = 0.01532
 Wu-Hausman F test: 5.79568 F(1,147) P-value = 0.01731
H0: Regressor is exogenous
Tests of endogeneity of: GROW
. ivendog GROW
Instruments: LEV CR GOV TANG SIZE L.GROW
Instrumented: GROW
 _cons -1.350566 .2795867 -4.83 0.000 -1.903064 -.7980688
 SIZE .0561461 .0103563 5.42 0.000 .0356808 .0766113
 TANG .1734984 .0722138 2.40 0.018 .0307952 .3162016
 GOV -.149723 .0518342 -2.89 0.004 -.2521538 -.0472922
 CR -.0049016 .0095596 -0.51 0.609 -.0237926 .0139894
 LEV -.2441052 .0925711 -2.64 0.009 -.427037 -.0611734
 GROW .4542529 .1788067 2.54 0.012 .100909 .8075968
 ROE Coef. Std. Err. t P>|t| [95% Conf. Interval]
 Total 2.40801219 154 .015636443 Root MSE = .13325
 Adj R-squared = .
 Residual 2.62780733 148 .017755455 R-squared = .
 Model -.219795141 6 -.036632523 Prob > F = 0.0000
 F( 6, 148) = 6.51
 Source SS df MS Number of obs = 155
Instrumental variables (2SLS) regression
. ivreg ROE LEV CR GOV (GROW=l.GROW) TANG SIZE
 + Kết quả kiểm tra với biến độc lập SIZE 
Do P-value = 0,00119 nhỏ hơn 0,05 nên biến SIZE là biến nội sinh. 
+ Kết quả kiểm tra với biến độc lập TANG 
Do P-value = 0,29057 lớn hơn 0,05 nên biến TANG là biến ngoại sinh. 
 Durbin-Wu-Hausman chi-sq test: 10.50164 Chi-sq(1) P-value = 0.00119
 Wu-Hausman F test: 10.68345 F(1,147) P-value = 0.00135
H0: Regressor is exogenous
Tests of endogeneity of: SIZE
. ivendog SIZE
Instruments: LEV CR GOV GROW TANG L.SIZE
Instrumented: SIZE
 _cons -1.293263 .2250109 -5.75 0.000 -1.737913 -.8486143
 TANG .1408005 .0565281 2.49 0.014 .029094 .2525069
 GROW .1251282 .0364215 3.44 0.001 .0531548 .1971015
 GOV -.1414161 .0416809 -3.39 0.001 -.2237827 -.0590494
 CR -.0037179 .0076583 -0.49 0.628 -.0188516 .0114159
 LEV -.1643319 .0667524 -2.46 0.015 -.2962427 -.0324211
 SIZE .0531041 .0083215 6.38 0.000 .0366598 .0695484
 ROE Coef. Std. Err. t P>|t| [95% Conf. Interval]
 Total 2.40801219 154 .015636443 Root MSE = .10699
 Adj R-squared = 0.2679
 Residual 1.69428595 148 .011447878 R-squared = 0.2964
 Model .713726242 6 .118954374 Prob > F = 0.0000
 F( 6, 148) = 9.88
 Source SS df MS Number of obs = 155
Instrumental variables (2SLS) regression
. ivreg ROE LEV CR GOV GROW TANG (SIZE=l.SIZE)
 Durbin-Wu-Hausman chi-sq test: 1.11697 Chi-sq(1) P-value = 0.29057
 Wu-Hausman F test: 1.06701 F(1,147) P-value = 0.30332
H0: Regressor is exogenous
Tests of endogeneity of: TANG
. ivendog TANG
Instruments: LEV CR GOV GROW SIZE L.TANG
Instrumented: TANG
 _cons -1.323808 .225272 -5.88 0.000 -1.768973 -.8786426
 SIZE .0544563 .0083179 6.55 0.000 .0380191 .0708934
 GROW .124434 .0364414 3.41 0.001 .0524213 .1964468
 GOV -.1487569 .0416316 -3.57 0.000 -.231026 -.0664879
 CR -.0040622 .0076703 -0.53 0.597 -.0192197 .0110952
 LEV -.1670931 .0667706 -2.50 0.013 -.29904 -.0351462
 TANG .1215807 .0601827 2.02 0.045 .0026523 .2405091
 ROE Coef. Std. Err. t P>|t| [95% Conf. Interval]
 Total 2.40801219 154 .015636443 Root MSE = .10703
 Adj R-squared = 0.2674
 Residual 1.69533344 148 .011454956 R-squared = 0.2960
 Model .712678749 6 .118779791 Prob > F = 0.0000
 F( 6, 148) = 10.01
 Source SS df MS Number of obs = 155
Instrumental variables (2SLS) regression
. ivreg ROE LEV CR GOV GROW (TANG=l.TANG) SIZE
 Phụ lục 14: Kết quả kiểm định tác động tuyến tính của SLEV tới tỷ suất 
sinh lời VCSH (ROE) 
- Mô hình OLS 
- Kiểm định hiện tượng đa cộng tuyến 
- Kiểm định hiện tượng phương sai thay đổi 
Do p-value = 0,0001 nhỏ hơn 0,05 => Có hiện tượng phương sai thay đổi 
 _cons -1.307799 .2034466 -6.43 0.000 -1.709261 -.9063362
 SIZE .0546388 .0076362 7.16 0.000 .0395703 .0697074
 TANG .1009444 .0529087 1.91 0.058 -.0034607 .2053495
 GROW .1578483 .0333746 4.73 0.000 .0919901 .2237066
 GOV -.1474352 .0380125 -3.88 0.000 -.2224456 -.0724248
 CR -.0040398 .0068984 -0.59 0.559 -.0176526 .0095729
 SLEV -.2332051 .0584148 -3.99 0.000 -.3484754 -.1179349
 ROE Coef. Std. Err. t P>|t| [95% Conf. Interval]
 Total 2.99698509 185 .016199919 Root MSE = .10723
 Adj R-squared = 0.2902
 Residual 2.05819985 179 .011498323 R-squared = 0.3132
 Model .938785241 6 .156464207 Prob > F = 0.0000
 F( 6, 179) = 13.61
 Source SS df MS Number of obs = 186
 Mean VIF 1.94
 GROW 1.04 0.965334
 TANG 1.16 0.860973
 CR 1.92 0.520477
 SLEV 2.05 0.488232
 GOV 2.63 0.380686
 SIZE 2.82 0.354861
 Variable VIF 1/VIF 
 Total 99.42 33 0.0000
 Kurtosis 2.37 1 0.1234
 Skewness 28.19 6 0.0001
 Heteroskedasticity 68.85 26 0.0000
 Source chi2 df p
Cameron & Trivedi's decomposition of IM-test
 Prob > chi2 = 0.0000
 chi2(26) = 68.85
 against Ha: unrestricted heteroskedasticity
White's test for Ho: homoskedasticity
 - Kiểm định hiện tượng tự tương quan 
Do p-value = 0,0014 nhỏ hơn 0,05 => Có hiện tượng tự tương quan 
- Mô hình FEM 
- Mô hình REM 
 Prob > F = 0.0014
 F( 1, 30) = 12.345
H0: no first-order autocorrelation
Wooldridge test for autocorrelation in panel data
F test that all u_i=0: F(30, 150) = 7.58 Prob > F = 0.0000
 rho .66234078 (fraction of variance due to u_i)
 sigma_e .07689913
 sigma_u .10770177
 _cons -1.505584 .7138739 -2.11 0.037 -2.916131 -.0950368
 SIZE .0644429 .0262871 2.45 0.015 .0125021 .1163837
 TANG -.0084231 .1358991 -0.06 0.951 -.2769469 .2601006
 GROW .1195542 .0320525 3.73 0.000 .0562215 .1828869
 GOV 0 (omitted)
 CR -.0095351 .0091316 -1.04 0.298 -.0275782 .0085081
 SLEV -.3697677 .0974804 -3.79 0.000 -.5623798 -.1771557
 ROE Coef. Std. Err. t P>|t| [95% Conf. Interval]
corr(u_i, Xb) = -0.5327 Prob > F = 0.0002
 F(5,150) = 5.33
 overall = 0.2051 max = 6
 between = 0.2553 avg = 6.0
R-sq: within = 0.1509 Obs per group: min = 6
Group variable: MACK Number of groups = 31
Fixed-effects (within) regression Number of obs = 186
 rho .52997541 (fraction of variance due to u_i)
 sigma_e .07689913
 sigma_u .08165616
 _cons -1.338968 .3541025 -3.78 0.000 -2.032997 -.6449402
 SIZE .0574115 .0132793 4.32 0.000 .0313846 .0834385
 TANG .0638489 .0848942 0.75 0.452 -.1025407 .2302386
 GROW .1250699 .0295484 4.23 0.000 .0671561 .1829838
 GOV -.1594924 .0699865 -2.28 0.023 -.2966634 -.0223215
 CR -.0073305 .0078254 -0.94 0.349 -.0226679 .008007
 SLEV -.3023243 .0755584 -4.00 0.000 -.450416 -.1542326
 ROE Coef. Std. Err. z P>|z| [95% Conf. Interval]
corr(u_i, X) = 0 (assumed) Prob > chi2 = 0.0000
 Wald chi2(6) = 42.68
 overall = 0.3016 max = 6
 between = 0.3850 avg = 6.0
R-sq: within = 0.1468 Obs per group: min = 6
Group variable: MACK Number of groups = 31
Random-effects GLS regression Number of obs = 186
 - Kiểm định Hausman 
Do p-value = 0,7467 lớn hơn 0,05 => Lựa chọn là mô hình REM. 
- Kiểm định phương sai thay đổi 
Do p-value = 0,0000 nhỏ hơn 0,05 => Có hiện tượng phương sai thay đổi 
- Mô hình GLS 
 Prob>chi2 = 0.7467
 = 2.70
 chi2(5) = (b-B)'[(V_b-V_B)^(-1)](b-B)
 Test: Ho: difference in coefficients not systematic
 B = inconsistent under Ha, efficient under Ho; obtained from xtreg
 b = consistent under Ho and Ha; obtained from xtreg
 SIZE .0644429 .0574115 .0070314 .0226864
 TANG -.0084231 .0638489 -.0722721 .1061204
 GROW .1195542 .1250699 -.0055158 .0124198
 CR -.0095351 -.0073305 -.0022046 .0047064
 SLEV -.3697677 -.3023243 -.0674434 .0615902
 FEM REM Difference S.E.
 (b) (B) (b-B) sqrt(diag(V_b-V_B))
 Coefficients 
 Prob > chibar2 = 0.0000
 chibar2(01) = 100.80
 Test: Var(u) = 0
 u .0066677 .0816562
 e .0059135 .0768991
 ROE .0161999 .1272789
 Var sd = sqrt(Var)
 Estimated results:
 ROE[MACK,t] = Xb + u[MACK] + e[MACK,t]
Breusch and Pagan Lagrangian multiplier test for random effects
 _cons -.9263552 .1724005 -5.37 0.000 -1.264254 -.5884563
 SIZE .0407286 .0066496 6.12 0.000 .0276956 .0537617
 TANG .0701348 .0349898 2.00 0.045 .001556 .1387136
 GROW .0421343 .018268 2.31 0.021 .0063297 .0779388
 GOV -.0994337 .0305826 -3.25 0.001 -.1593744 -.039493
 CR -.0071516 .0046994 -1.52 0.128 -.0163623 .002059
 SLEV -.2016365 .0409922 -4.92 0.000 -.2819797 -.1212933
 ROE Coef. Std. Err. z P>|z| [95% Conf. Interval]
 Prob > chi2 = 0.0000
 Wald chi2(6) = 48.56
Estimated coefficients = 7 Time periods = 6
Estimated autocorrelations = 1 Number of groups = 31
Estimated covariances = 31 Number of obs = 186
Correlation: common AR(1) coefficient for all panels (0.4734)
Panels: heteroskedastic
Coefficients: generalized least squares
Cross-sectional time-series FGLS regression
 - Mô hình GMM 
 Difference (null H = exogenous): chi2(3) = 12.80 Prob > chi2 = 0.005
 Sargan test excluding group: chi2(18) = 29.56 Prob > chi2 = 0.042
 iv(CR GOV TANG)
 Difference (null H = exogenous): chi2(9) = 31.63 Prob > chi2 = 0.000
 Sargan test excluding group: chi2(12) = 10.73 Prob > chi2 = 0.552
 GMM instruments for levels
Difference-in-Sargan tests of exogeneity of instrument subsets:
 (Not robust, but not weakened by many instruments.)
Sargan test of overid. restrictions: chi2(21) = 42.37 Prob > chi2 = 0.004
Arellano-Bond test for AR(2) in first differences: z = -1.05 Pr > z = 0.293
Arellano-Bond test for AR(1) in first differences: z = -2.13 Pr > z = 0.033
 DL.(L.SLEV L.GROW L.SIZE)
 GMM-type (missing=0, separate instruments for each period unless collapsed)
 _cons
 CR GOV TANG
 Standard
Instruments for levels equation
 L(2/3).(L.SLEV L.GROW L.SIZE)
 GMM-type (missing=0, separate instruments for each period unless collapsed)
 D.(CR GOV TANG)
 Standard
Instruments for first differences equation
 _cons -.7963793 .3274357 -2.43 0.015 -1.438141 -.1546171
 SIZE .043875 .0116175 3.78 0.000 .021105 .0666449
 TANG -.0016645 .0505796 -0.03 0.974 -.1007987 .0974698
 GROW .2290531 .0553453 4.14 0.000 .1205783 .337528
 GOV -.0929749 .048125 -1.93 0.053 -.1872983 .0013484
 CR -.0349962 .0113192 -3.09 0.002 -.0571814 -.012811
 SLEV -.5903064 .1396856 -4.23 0.000 -.8640852 -.3165276
 ROE Coef. Std. Err. z P>|z| [95% Conf. Interval]
Prob > chi2 = 0.000 max = 6
Wald chi2(6) = 59.78 avg = 6.00
Number of instruments = 28 Obs per group: min = 6
Time variable : YEAR Number of groups = 31
Group variable: MACK Number of obs = 186
Dynamic panel-data estimation, one-step system GMM
 - Kiểm tra hiện tượng nội sinh với biến phụ thuộc ROE 
+ Kết quả kiểm tra với biến độc lập SLEV 
Do P-value = 0,00537 nhỏ hơn 0,05 nên biến SLEV là biến nội sinh. 
+ Kết quả kiểm tra với biến độc lập CR 
Do P-value = 0,05803 lớn hơn 0,05 nên biến CR là biến ngoại sinh. 
 Durbin-Wu-Hausman chi-sq test: 7.75177 Chi-sq(1) P-value = 0.00537
 Wu-Hausman F test: 7.73870 F(1,147) P-value = 0.00611
H0: Regressor is exogenous
Tests of endogeneity of: SLEV
. ivendog SLEV
Instruments: CR GOV GROW TANG SIZE L.SLEV
Instrumented: SLEV
 _cons -1.385781 .2208881 -6.27 0.000 -1.822283 -.9492789
 SIZE .055348 .0083654 6.62 0.000 .038817 .071879
 TANG .1256133 .0569231 2.21 0.029 .0131263 .2381003
 GROW .1221647 .0358979 3.40 0.001 .051226 .1931035
 GOV -.1503101 .0412512 -3.64 0.000 -.2318276 -.0687927
 CR .0008038 .007832 0.10 0.918 -.0146732 .0162808
 SLEV -.1249991 .0788141 -1.59 0.115 -.2807454 .0307472
 ROE Coef. Std. Err. t P>|t| [95% Conf. Interval]
 Total 2.40801219 154 .015636443 Root MSE = .10512
 Adj R-squared = 0.2933
 Residual 1.63545599 148 .011050378 R-squared = 0.3208
 Model .772556203 6 .128759367 Prob > F = 0.0000
 F( 6, 148) = 10.12
 Source SS df MS Number of obs = 155
Instrumental variables (2SLS) regression
. ivreg ROE (SLEV =l.SLEV) CR GOV GROW TANG SIZE
 Durbin-Wu-Hausman chi-sq test: 3.59275 Chi-sq(1) P-value = 0.05803
 Wu-Hausman F test: 3.48817 F(1,147) P-value = 0.06380
H0: Regressor is exogenous
Tests of endogeneity of: CR
. ivendog CR
Instruments: SLEV GOV GROW TANG SIZE L.CR
Instrumented: CR
 _cons -1.359226 .2211286 -6.15 0.000 -1.796204 -.9222492
 SIZE .0588834 .008211 7.17 0.000 .0426574 .0751095
 TANG .0844509 .0572762 1.47 0.142 -.0287339 .1976357
 GROW .1308951 .0355482 3.68 0.000 .0606475 .2011426
 GOV -.1576952 .0408692 -3.86 0.000 -.2384577 -.0769327
 SLEV -.3139232 .071747 -4.38 0.000 -.455704 -.1721424
 CR -.0190113 .0090443 -2.10 0.037 -.036884 -.0011386
 ROE Coef. Std. Err. t P>|t| [95% Conf. Interval]
 Total 2.40801219 154 .015636443 Root MSE = .10452
 Adj R-squared = 0.3014
 Residual 1.61676154 148 .010924064 R-squared = 0.3286
 Model .79125065 6 .131875108 Prob > F = 0.0000
 F( 6, 148) = 12.94
 Source SS df MS Number of obs = 155
Instrumental variables (2SLS) regression
. ivreg ROE SLEV (CR=l.CR) GOV GROW TANG SIZE
 + Kết quả kiểm tra với biến độc lập GOV 
Do P-value = 1,0 lớn hơn 0,05 nên biến GOV là biến ngoại sinh. 
+ Kết quả kiểm tra với biến độc lập GROW 
Do P-value = 0,02175 nhỏ hơn 0,05 nên biến GROW là biến nội sinh. 
 Durbin-Wu-Hausman chi-sq test: 0.00000 Chi-sq(1) P-value = 1.00000
 Wu-Hausman F test: 0.00000 F(1,147) P-value = 1.00000
H0: Regressor is exogenous
Tests of endogeneity of: GOV
. ivendog GOV
Instruments: SLEV CR GROW TANG SIZE L.GOV
Instrumented: GOV
 _cons -1.409198 .2177555 -6.47 0.000 -1.839509 -.9788861
 SIZE .058928 .0081476 7.23 0.000 .0428273 .0750286
 TANG .1055946 .0556755 1.90 0.060 -.0044271 .2156162
 GROW .1308125 .0352736 3.71 0.000 .0611076 .2005174
 CR -.0084628 .0069358 -1.22 0.224 -.0221687 .0052431
 SLEV -.2508157 .0625099 -4.01 0.000 -.3743429 -.1272885
 GOV -.1605028 .0405252 -3.96 0.000 -.2405855 -.0804201
 ROE Coef. Std. Err. t P>|t| [95% Conf. Interval]
 Total 2.40801219 154 .015636443 Root MSE = .10371
 Adj R-squared = 0.3121
 Residual 1.59188198 148 .010755959 R-squared = 0.3389
 Model .816130207 6 .136021701 Prob > F = 0.0000
 F( 6, 148) = 12.65
 Source SS df MS Number of obs = 155
Instrumental variables (2SLS) regression
. ivreg ROE SLEV CR (GOV =l.GOV) GROW TANG SIZE
 Durbin-Wu-Hausman chi-sq test: 5.26553 Chi-sq(1) P-value = 0.02175
 Wu-Hausman F test: 5.16937 F(1,147) P-value = 0.02444
H0: Regressor is exogenous
Tests of endogeneity of: GROW
. ivendog GROW
Instruments: SLEV CR GOV TANG SIZE L.GROW
Instrumented: GROW
 _cons -1.436452 .2640859 -5.44 0.000 -1.958318 -.9145862
 SIZE .0604654 .0099006 6.11 0.000 .0409006 .0800303
 TANG .1239604 .0681419 1.82 0.071 -.0106964 .2586172
 GOV -.1630919 .049091 -3.32 0.001 -.2601016 -.0660821
 CR -.0085514 .0083985 -1.02 0.310 -.0251479 .0080451
 SLEV -.3140634 .0830412 -3.78 0.000 -.4781631 -.1499637
 GROW .4238197 .1638947 2.59 0.011 .0999437 .7476958
 ROE Coef. Std. Err. t P>|t| [95% Conf. Interval]
 Total 2.40801219 154 .015636443 Root MSE = .12558
 Adj R-squared = -0.0086
 Residual 2.33405803 148 .015770662 R-squared = 0.0307
 Model .073954163 6 .012325694 Prob > F = 0.0000
 F( 6, 148) = 8.18
 Source SS df MS Number of obs = 155
Instrumental variables (2SLS) regression
. ivreg ROE SLEV CR GOV (GROW=l.GROW) TANG SIZE
 + Kết quả kiểm tra với biến độc lập SIZE 
Do P-value = 0,00145 nhỏ hơn 0,05 nên biến SIZE là biến nội sinh. 
+ Kết quả kiểm tra với biến độc lập TANG 
Do P-value = 0,44767 lớn hơn 0,05 nên biến TANG là biến ngoại sinh. 
 Durbin-Wu-Hausman chi-sq test: 10.13659 Chi-sq(1) P-value = 0.00145
 Wu-Hausman F test: 10.28609 F(1,147) P-value = 0.00165
H0: Regressor is exogenous
Tests of endogeneity of: SIZE
. ivendog SIZE
Instruments: SLEV CR GOV GROW TANG L.SIZE
Instrumented: SIZE
 _cons -1.361467 .218332 -6.24 0.000 -1.792917 -.9300157
 TANG .1040825 .055687 1.87 0.064 -.0059618 .2141269
 GROW .1306339 .0352795 3.70 0.000 .0609172 .2003505
 GOV -.1534925 .0405946 -3.78 0.000 -.2337123 -.0732726
 CR -.0084683 .0069369 -1.22 0.224 -.0221766 .0052399
 SLEV -.247773 .062528 -3.96 0.000 -.3713361 -.1242099
 SIZE .0571113 .0081699 6.99 0.000 .0409667 .0732559
 ROE Coef. Std. Err. t P>|t| [95% Conf. Interval]
 Total 2.40801219 154 .015636443 Root MSE = .10373
 Adj R-squared = 0.3119
 Residual 1.59241672 148 .010759572 R-squared = 0.3387
 Model .815595468 6 .135932578 Prob > F = 0.0000
 F( 6, 148) = 12.07
 Source SS df MS Number of obs = 155
Instrumental variables (2SLS) regression
. ivreg ROE SLEV CR GOV GROW TANG (SIZE=l.SIZE)
 Durbin-Wu-Hausman chi-sq test: 0.57653 Chi-sq(1) P-value = 0.44767
 Wu-Hausman F test: 0.54882 F(1,147) P-value = 0.45998
H0: Regressor is exogenous
Tests of endogeneity of: TANG
. ivendog TANG
Instruments: SLEV CR GOV GROW SIZE L.TANG
Instrumented: TANG
 _cons -1.396952 .2184343 -6.40 0.000 -1.828605 -.9652993
 SIZE .058659 .0081577 7.19 0.000 .0425384 .0747795
 GROW .1304328 .035286 3.70 0.000 .0607033 .2001623
 GOV -.1608157 .0405374 -3.97 0.000 -.2409226 -.0807088
 CR -.0089322 .0069663 -1.28 0.202 -.0226985 .004834
 SLEV -.2538427 .0626584 -4.05 0.000 -.3776635 -.130022
 TANG .0905025 .0592897 1.53 0.129 -.0266612 .2076661
 ROE Coef. Std. Err. t P>|t| [95% Conf. Interval]
 Total 2.40801219 154 .015636443 Root MSE = .10374
 Adj R-squared = 0.3118
 Residual 1.59267234 148 .0107613 R-squared = 0.3386
 Model .815339855 6 .135889976 Prob > F = 0.0000
 F( 6, 148) = 12.43
 Source SS df MS Number of obs = 155
Instrumental variables (2SLS) regression
. ivreg ROE SLEV CR GOV GROW (TANG=l.TANG) SIZE
 Phụ lục 15: Kết quả kiểm định tác động tuyến tính của LLEV tới tỷ suất 
sinh lời VCSH (ROE) (mô hình 6) 
- Mô hình OLS 
- Kiểm định hiện tượng đa cộng tuyến 
- Kiểm định hiện tượng phương sai thay đổi 
Do p-value = 0,0000 nhỏ hơn 0,05 => Có hiện tượng phương sai thay đổi. 
 _cons -1.339528 .209912 -6.38 0.000 -1.753749 -.9253079
 SIZE .0501077 .0076522 6.55 0.000 .0350076 .0652079
 TANG .1061781 .0547735 1.94 0.054 -.0019066 .2142629
 GROW .1379675 .0338686 4.07 0.000 .0711344 .2048006
 GOV -.1370819 .0386967 -3.54 0.001 -.2134423 -.0607216
 CR .0165871 .0053404 3.11 0.002 .0060488 .0271254
 LLEV .2770091 .1017879 2.72 0.007 .0761505 .4778678
 ROE Coef. Std. Err. t P>|t| [95% Conf. Interval]
 Total 2.99698509 185 .016199919 Root MSE = .10966
 Adj R-squared = 0.2577
 Residual 2.15240194 179 .012024592 R-squared = 0.2818
 Model .844583149 6 .140763858 Prob > F = 0.0000
 F( 6, 179) = 11.71
 Source SS df MS Number of obs = 186
 Mean VIF 1.63
 GROW 1.02 0.980280
 CR 1.10 0.908207
 LLEV 1.14 0.875225
 TANG 1.19 0.840117
 GOV 2.60 0.384158
 SIZE 2.71 0.369554
 Variable VIF 1/VIF 
 Total 96.15 33 0.0000
 Kurtosis 2.03 1 0.1538
 Skewness 26.87 6 0.0002
 Heteroskedasticity 67.25 26 0.0000
 Source chi2 df p
Cameron & Trivedi's decomposition of IM-test
 Prob > chi2 = 0.0000
 chi2(26) = 67.25
 against Ha: unrestricted heteroskedasticity
White's test for Ho: homoskedasticity
 - Kiểm định hiện tượng tự tương quan 
Do p-value = 0,0037 nhỏ hơn 0,05 => Có hiện tượng tự tương quan 
- Mô hình FEM 
- Mô hình REM 
 Prob > F = 0.0004
 F( 1, 30) = 15.584
H0: no first-order autocorrelation
Wooldridge test for autocorrelation in panel data
F test that all u_i=0: F(30, 150) = 7.06 Prob > F = 0.0000
 rho .56297139 (fraction of variance due to u_i)
 sigma_e .07977965
 sigma_u .09054832
 _cons -1.090947 .7307255 -1.49 0.138 -2.534791 .3528973
 SIZE .0410363 .0264501 1.55 0.123 -.0112265 .0932991
 TANG .0809629 .1397827 0.58 0.563 -.1952344 .3571602
 GROW .0838297 .0317397 2.64 0.009 .021115 .1465443
 GOV 0 (omitted)
 CR .0091387 .007854 1.16 0.246 -.0063801 .0246576
 LLEV .2776268 .1679595 1.65 0.100 -.0542452 .6094989
 ROE Coef. Std. Err. t P>|t| [95% Conf. Interval]
corr(u_i, Xb) = -0.1681 Prob > F = 0.0181
 F(5,150) = 2.83
 overall = 0.2029 max = 6
 between = 0.2676 avg = 6.0
R-sq: within = 0.0861 Obs per group: min = 6
Group variable: MACK Number of groups = 31
Fixed-effects (within) regression Number of obs = 186
 rho .51381824 (fraction of variance due to u_i)
 sigma_e .07977965
 sigma_u .08201581
 _cons -1.254507 .3586086 -3.50 0.000 -1.957367 -.5516468
 SIZE .0473334 .01315 3.60 0.000 .0215599 .0731068
 TANG .0983094 .0868978 1.13 0.258 -.0720073 .268626
 GROW .093262 .029352 3.18 0.001 .0357332 .1507908
 GOV -.1261546 .0701075 -1.80 0.072 -.2635629 .0112536
 CR .0119654 .0064503 1.86 0.064 -.000677 .0246077
 LLEV .2725342 .132303 2.06 0.039 .0132251 .5318433
 ROE Coef. Std. Err. z P>|z| [95% Conf. Interval]
corr(u_i, X) = 0 (assumed) Prob > chi2 = 0.0000
 Wald chi2(6) = 29.87
 overall = 0.2751 max = 6
 between = 0.3795 avg = 6.0
R-sq: within = 0.0856 Obs per group: min = 6
Group variable: MACK Number of groups = 31
Random-effects GLS regression Number of obs = 186
 - Kiểm định Hausman 
Do p-value = 0,8381 lớn hơn 0,05 => lựa chọn là mô hình REM. 
- Kiểm định phương sai thay đổi của mô hình 
Do p-value = 0,000 nhỏ hơn 0,05 => Có hiện tượng phương sai thay đổi 
- Mô hình GLS 
 Prob>chi2 = 0.8381
 = 2.08
 chi2(5) = (b-B)'[(V_b-V_B)^(-1)](b-B)
 Test: Ho: difference in coefficients not systematic
 B = inconsistent under Ha, efficient under Ho; obtained from xtreg
 b = consistent under Ho and Ha; obtained from xtreg
 SIZE .0410363 .0473334 -.0062971 .0229496
 TANG .0809629 .0983094 -.0173465 .1094895
 GROW .0838297 .093262 -.0094323 .0120777
 CR .0091387 .0119654 -.0028266 .004481
 LLEV .2776268 .2725342 .0050927 .1034713
 FEM REM Difference S.E.
 (b) (B) (b-B) sqrt(diag(V_b-V_B))
 Coefficients 
 Prob > chibar2 = 0.0000
 chibar2(01) = 95.28
 Test: Var(u) = 0
 u .0067266 .0820158
 e .0063648 .0797797
 ROE .0161999 .1272789
 Var sd = sqrt(Var)
 Estimated results:
 ROE[MACK,t] = Xb + u[MACK] + e[MACK,t]
Breusch and Pagan Lagrangian multiplier test for random effects
 _cons -.9551869 .1854934 -5.15 0.000 -1.318747 -.5916265
 SIZE .0368312 .0066866 5.51 0.000 .0237257 .0499366
 TANG .1186686 .0346368 3.43 0.001 .0507817 .1865555
 GROW .018178 .0172348 1.05 0.292 -.0156015 .0519576
 GOV -.1073717 .028351 -3.79 0.000 -.1629386 -.0518047
 CR .0101613 .0047794 2.13 0.033 .0007938 .0195287
 LLEV .1580683 .0640931 2.47 0.014 .0324481 .2836885
 ROE Coef. Std. Err. z P>|z| [95% Conf. Interval]
 Prob > chi2 = 0.0000
 Wald chi2(6) = 41.97
Estimated coefficients = 7 Time periods = 6
Estimated autocorrelations = 1 Number of groups = 31
Estimated covariances = 31 Number of obs = 186
Correlation: common AR(1) coefficient for all panels (0.4584)
Panels: heteroskedastic
Coefficients: generalized least squares
Cross-sectional time-series FGLS regression
 - Mô hình GMM 
 Difference (null H = exogenous): chi2(4) = 6.97 Prob > chi2 = 0.137
 Sargan test excluding group: chi2(6) = 11.70 Prob > chi2 = 0.069
 iv(LLEV CR GOV TANG)
 Difference (null H = exogenous): chi2(6) = 15.84 Prob > chi2 = 0.015
 Sargan test excluding group: chi2(4) = 2.83 Prob > chi2 = 0.586
 GMM instruments for levels
Difference-in-Sargan tests of exogeneity of instrument subsets:
 (Not robust, but not weakened by many instruments.)
Sargan test of overid. restrictions: chi2(10) = 18.67 Prob > chi2 = 0.045
Arellano-Bond test for AR(2) in first differences: z = -1.74 Pr > z = 0.082
Arellano-Bond test for AR(1) in first differences: z = -2.34 Pr > z = 0.019
 DL.(L.GROW L.SIZE)
 GMM-type (missing=0, separate instruments for each period unless collapsed)
 _cons
 LLEV CR GOV TANG
 Standard
Instruments for levels equation
 L2.(L.GROW L.SIZE)
 GMM-type (missing=0, separate instruments for each period unless collapsed)
 D.(LLEV CR GOV TANG)
 Standard
Instruments for first differences equation
 _cons -1.496699 .5863232 -2.55 0.011 -2.645871 -.3475264
 SIZE .0554342 .0215363 2.57 0.010 .0132239 .0976446
 TANG .1558134 .0557725 2.79 0.005 .0465014 .2651255
 GROW .3203796 .0909025 3.52 0.000 .142214 .4985453
 GOV -.1514176 .0867085 -1.75 0.081 -.3213631 .0185278
 CR .0173756 .0054357 3.20 0.001 .0067218 .0280294
 LLEV .2600849 .0893844 2.91 0.004 .0848948 .4352751
 ROE Coef. Std. Err. z P>|z| [95% Conf. Interval]
Prob > chi2 = 0.000 max = 6
Wald chi2(6) = 35.62 avg = 6.00
Number of instruments = 17 Obs per group: min = 6
Time variable : YEAR Number of groups = 31
Group variable: MACK Number of obs = 186
Dynamic panel-data estimation, one-step system GMM
 - Kiểm tra hiện tượng nội sinh với biến phụ thuộc ROE 
+ Kết quả kiểm tra với biến độc lập LLEV 
Do P-value = 0,37605 lớn hơn 0,05 nên biến LLEV là biến ngoại sinh. 
+ Kết quả kiểm tra với biến độc lập CR 
Do P-value = 0,23510 lớn hơn 0,05 nên biến CR là biến ngoại sinh. 
 Durbin-Wu-Hausman chi-sq test: 0.78357 Chi-sq(1) P-value = 0.37605
 Wu-Hausman F test: 0.74690 F(1,147) P-value = 0.38887
H0: Regressor is exogenous
Tests of endogeneity of: LLEV
. ivendog LLEV
Instruments: CR GOV GROW TANG SIZE L.LLEV
Instrumented: LLEV
 _cons -1.458269 .2275748 -6.41 0.000 -1.907985 -1.008554
 SIZE .054734 .0082892 6.60 0.000 .0383536 .0711143
 TANG .1006796 .0591602 1.70 0.091 -.0162283 .2175874
 GROW .1131403 .0361551 3.13 0.002 .0416933 .1845873
 GOV -.1496557 .041682 -3.59 0.000 -.2320245 -.0672869
 CR .0126444 .0054526 2.32 0.022 .0018694 .0234194
 LLEV .3129275 .1208844 2.59 0.011 .0740451 .55181
 ROE Coef. Std. Err. t P>|t| [95% Conf. Interval]
 Total 2.40801219 154 .015636443 Root MSE = .1071
 Adj R-squared = 0.2664
 Residual 1.69759681 148 .011470249 R-squared = 0.2950
 Model .710415386 6 .118402564 Prob > F = 0.0000
 F( 6, 148) = 10.46
 Source SS df MS Number of obs = 155
Instrumental variables (2SLS) regression
. ivreg ROE (LLEV =l.LLEV) CR GOV GROW TANG SIZE
 Durbin-Wu-Hausman chi-sq test: 1.40974 Chi-sq(1) P-value = 0.23510
 Wu-Hausman F test: 1.34925 F(1,147) P-value = 0.24729
H0: Regressor is exogenous
Tests of endogeneity of: CR
. ivendog CR
Instruments: LLEV GOV GROW TANG SIZE L.CR
Instrumented: CR
 _cons -1.401705 .2300639 -6.09 0.000 -1.856339 -.9470701
 SIZE .0530306 .0083521 6.35 0.000 .0365258 .0695354
 TANG .1023603 .0588597 1.74 0.084 -.0139537 .2186743
 GROW .1105846 .0362608 3.05 0.003 .0389289 .1822403
 GOV -.1429349 .0419387 -3.41 0.001 -.2258109 -.060059
 LLEV .2531314 .1084132 2.33 0.021 .0388937 .4673691
 CR .0084824 .0063351 1.34 0.183 -.0040365 .0210012
 ROE Coef. Std. Err. t P>|t| [95% Conf. Interval]
 Total 2.40801219 154 .015636443 Root MSE = .1072
 Adj R-squared = 0.2650
 Residual 1.7008887 148 .011492491 R-squared = 0.2937
 Model .707123486 6 .117853914 Prob > F = 0.0000
 F( 6, 148) = 9.79
 Source SS df MS Number of obs = 155
Instrumental variables (2SLS) regression
. ivreg ROE LLEV (CR=l.CR) GOV GROW TANG SIZE
 + Kết quả kiểm tra với biến độc lập GOV 
Do P-value = 1,0 lớn hơn 0,05 nên biến GOV là biến ngoại sinh. 
+ Kết quả kiểm tra với biến độc lập GROW 
Do P-value = 0,03359 lớn hơn 0,05 nên biến GROW là biến ngoại sinh. 
 Durbin-Wu-Hausman chi-sq test: 0.00000 Chi-sq(1) P-value = 1.00000
 Wu-Hausman F test: 0.00000 F(1,147) P-value = 1.00000
H0: Regressor is exogenous
Tests of endogeneity of: GOV
. ivendog GOV
Instruments: LLEV CR GROW TANG SIZE L.GOV
Instrumented: GOV
 _cons -1.443787 .2268093 -6.37 0.000 -1.89199 -.9955839
 SIZE .0542889 .0082678 6.57 0.000 .0379508 .070627
 TANG .1074589 .0585999 1.83 0.069 -.0083416 .2232594
 GROW .1132057 .0361315 3.13 0.002 .0418055 .184606
 CR .012246 .0054296 2.26 0.026 .0015165 .0229755
 LLEV .2655978 .107703 2.47 0.015 .0527636 .4784321
 GOV -.1482231 .0416219 -3.56 0.000 -.2304731 -.0659731
 ROE Coef. Std. Err. t P>|t| [95% Conf. Interval]
 Total 2.40801219 154 .015636443 Root MSE = .10703
 Adj R-squared = 0.2674
 Residual 1.69538463 148 .011455302 R-squared = 0.2959
 Model .712627559 6 .11877126 Prob > F = 0.0000
 F( 6, 148) = 10.37
 Source SS df MS Number of obs = 155
Instrumental variables (2SLS) regression
. ivreg ROE LLEV CR (GOV =l.GOV) GROW TANG SIZE
 Durbin-Wu-Hausman chi-sq test: 4.51541 Chi-sq(1) P-value = 0.03359
 Wu-Hausman F test: 4.41085 F(1,147) P-value = 0.03742
H0: Regressor is exogenous
Tests of endogeneity of: GROW
. ivendog GROW
Instruments: LLEV CR GOV TANG SIZE L.GROW
Instrumented: GROW
 _cons -1.457728 .2689029 -5.42 0.000 -1.989113 -.9263431
 SIZE .0540027 .0097992 5.51 0.000 .0346382 .0733672
 TANG .1354799 .0712627 1.90 0.059 -.0053439 .2763036
 GOV -.1456646 .0493466 -2.95 0.004 -.2431795 -.0481498
 CR .016642 .0069063 2.41 0.017 .0029944 .0302896
 LLEV .2621624 .1276507 2.05 0.042 .009909 .5144159
 GROW .3927295 .1651789 2.38 0.019 .0663157 .7191432
 ROE Coef. Std. Err. t P>|t| [95% Conf. Interval]
 Total 2.40801219 154 .015636443 Root MSE = .12684
 Adj R-squared = -0.0289
 Residual 2.38098664 148 .016087748 R-squared = 0.0112
 Model .027025552 6 .004504259 Prob > F = 0.0000
 F( 6, 148) = 7.16
 Source SS df MS Number of obs = 155
Instrumental variables (2SLS) regression
. ivreg ROE LLEV CR GOV (GROW=l.GROW) TANG SIZE
 + Kết quả kiểm tra với biến độc lập SIZE 
Do P-value = 0,00065 nhỏ hơn 0,05 nên biến SIZE là biến nội sinh. 
+ Kết quả kiểm tra với biến độc lập TANG 
Do P-value = 0,30036 lớn hơn 0,05 nên biến TANG là biến ngoại sinh. 
 Durbin-Wu-Hausman chi-sq test: 11.63334 Chi-sq(1) P-value = 0.00065
 Wu-Hausman F test: 11.92816 F(1,147) P-value = 0.00072
H0: Regressor is exogenous
Tests of endogeneity of: SIZE
. ivendog SIZE
Instruments: LLEV CR GOV GROW TANG L.SIZE
Instrumented: SIZE
 _cons -1.390528 .2274142 -6.11 0.000 -1.839926 -.9411296
 TANG .1056903 .0586133 1.80 0.073 -.0101367 .2215173
 GROW .1132438 .0361383 3.13 0.002 .0418302 .1846575
 GOV -.1406277 .0416921 -3.37 0.001 -.2230163 -.058239
 CR .0119651 .0054312 2.20 0.029 .0012323 .0226979
 LLEV .2624893 .1077272 2.44 0.016 .0496071 .4753714
 SIZE .0523409 .0082899 6.31 0.000 .035959 .0687229
 ROE Coef. Std. Err. t P>|t| [95% Conf. Interval]
 Total 2.40801219 154 .015636443 Root MSE = .10705
 Adj R-squared = 0.2671
 Residual 1.69602054 148 .011459598 R-squared = 0.2957
 Model .711991648 6 .118665275 Prob > F = 0.0000
 F( 6, 148) = 9.82
 Source SS df MS Number of obs = 155
Instrumental variables (2SLS) regression
. ivreg ROE LLEV CR GOV GROW TANG (SIZE=l.SIZE)
 Durbin-Wu-Hausman chi-sq test: 1.07259 Chi-sq(1) P-value = 0.30036
 Wu-Hausman F test: 1.02432 F(1,147) P-value = 0.31316
H0: Regressor is exogenous
Tests of endogeneity of: TANG
. ivendog TANG
Instruments: LLEV CR GOV GROW SIZE L.TANG
Instrumented: TANG
 _cons -1.42896 .2273922 -6.28 0.000 -1.878315 -.9796053
 SIZE .0538877 .0082813 6.51 0.000 .0375229 .0702525
 GROW .1123597 .0361587 3.11 0.002 .0409057 .1838137
 GOV -.148644 .0416442 -3.57 0.000 -.230938 -.06635
 CR .0119878 .0054382 2.20 0.029 .0012413 .0227343
 LLEV .2763392 .1082772 2.55 0.012 .0623703 .4903082
 TANG .0852591 .0626015 1.36 0.175 -.0384491 .2089674
 ROE Coef. Std. Err. t P>|t| [95% Conf. Interval]
 Total 2.40801219 154 .015636443 Root MSE = .10708
 Adj R-squared = 0.2667
 Residual 1.69702866 148 .01146641 R-squared = 0.2953
 Model .710983531 6 .118497255 Prob > F = 0.0000
 F( 6, 148) = 10.11
 Source SS df MS Number of obs = 155
Instrumental variables (2SLS) regression
. ivreg ROE LLEV CR GOV GROW (TANG=l.TANG) SIZE
 Phụ lục 16: Kết quả kiểm định tác động tuyến tính của DR tới WACC 
(mô hình 7) 
- Mô hình OLS 
- Kiểm định hiện tượng đa cộng tuyến 
- Kiểm định hiện tượng phương sai thay đổi 
Do p-value = 0,0000 nhỏ hơn 0,05 => Có hiện tượng phương sai thay đổi 
- Kiểm định hiện tượng tự tương quan 
 _cons .0198625 .0035355 5.62 0.000 .0128862 .0268388
 RISK .0960591 .0449033 2.14 0.034 .0074545 .1846637
 GROW -.0004234 .0052691 -0.08 0.936 -.0108205 .0099737
 TANG .0150826 .0079262 1.90 0.059 -.0005577 .0307229
 CR .0070981 .0009205 7.71 0.000 .0052817 .0089144
 DR .0137375 .0069385 1.98 0.049 .0000463 .0274288
 WACC Coef. Std. Err. t P>|t| [95% Conf. Interval]
 Total .076809141 185 .000415185 Root MSE = .01687
 Adj R-squared = 0.3146
 Residual .051224112 180 .000284578 R-squared = 0.3331
 Model .025585029 5 .005117006 Prob > F = 0.0000
 F( 5, 180) = 17.98
 Source SS df MS Number of obs = 186
 Mean VIF 1.22
 GROW 1.04 0.958537
 TANG 1.05 0.949464
 DR 1.28 0.782759
 RISK 1.33 0.750546
 CR 1.38 0.723483
 Variable VIF 1/VIF 
 Total 68.74 26 0.0000
 Kurtosis 3.01 1 0.0830
 Skewness 8.42 5 0.1346
 Heteroskedasticity 57.31 20 0.0000
 Source chi2 df p
Cameron & Trivedi's decomposition of IM-test
 Prob > chi2 = 0.0000
 chi2(20) = 57.31
 against Ha: unrestricted heteroskedasticity
White's test for Ho: homoskedasticity
 Prob > F = 0.0306
 F( 1, 30) = 5.153
H0: no first-order autocorrelation
Wooldridge test for autocorrelation in panel data
 Do p-value = 0,0306 nhỏ hơn 0,05 => Có hiện tượng tự tương quan 
- Mô hình FEM 
- Mô hình REM 
 - Kiểm định Hausman 
Do p-value = 0,0187 nhỏ hơn 0,05 => Lựa chọn mô hình FEM 
- Kiểm định phương sai thay đổi của mô hình 
Do p-value = 0,00 nhỏ hơn 0,05 => Có hiện tượng phương sai sai số thay 
đổi 
- Mô hình GLS 
 Prob>chi2 = 0.0187
 = 11.82
 chi2(4) = (b-B)'[(V_b-V_B)^(-1)](b-B)
 Test: Ho: difference in coefficients not systematic
 B = inconsistent under Ha, efficient under Ho; obtained from xtreg
 b = consistent under Ho and Ha; obtained from xtreg
 GROW -.0053177 -.0050655 -.0002522 .0011327
 TANG .0274943 .0198168 .0076775 .0136797
 CR .0028267 .0038993 -.0010726 .0004513
 DR -.0064066 .0012576 -.0076642 .0090016
 FEM REM Difference S.E.
 (b) (B) (b-B) sqrt(diag(V_b-V_B))
 Coefficients 
. hausman FEM REM
Prob>chi2 = 0.0000
chi2 (31) = 1445.93
H0: sigma(i)^2 = sigma^2 for all i
in fixed effect regression model
Modified Wald test for groupwise heteroskedasticity
 _cons .020757 .0032378 6.41 0.000 .014411 .0271031
 RISK .1209279 .0547299 2.21 0.027 .0136593 .2281965
 GROW -.0048506 .0022325 -2.17 0.030 -.0092263 -.000475
 TANG .0085904 .0066287 1.30 0.195 -.0044016 .0215824
 CR .0050646 .0010746 4.71 0.000 .0029584 .0071708
 DR .014762 .0055899 2.64 0.008 .003806 .0257179
 WACC Coef. Std. Err. z P>|z| [95% Conf. Interval]
 Prob > chi2 = 0.0000
 Wald chi2(5) = 39.73
Estimated coefficients = 6 Time periods = 6
Estimated autocorrelations = 1 Number of groups = 31
Estimated covariances = 31 Number of obs = 186
Correlation: common AR(1) coefficient for all panels (0.5192)
Panels: heteroskedastic
Coefficients: generalized least squares
Cross-sectional time-series FGLS regression
 Phụ lục 17: Hệ số Z’’ của các DN thương mại dầu khí trong mẫu nghiên 
cứu 
STT Mã CK 2014 2015 2016 2017 2018 2019 
1 ASP 7,72 5,88 3,78 0,71 0,97 0,51 
2 CNG 12,74 10,21 15,91 449,03 1158,12 - 
3 COM - - - - - 36,40 
4 GAS 11,91 14,40 10,88 10,30 16,46 26,70 
5 HFC 1,63 1,09 0,35 0,11 0,28 0,01 
6 HTC - - - 3,49 4,62 6,86 
7 MTG -0,59 0,31 1,43 -1,84 - - 
8 OIL 3,62 5,34 5,64 9,18 6,90 4,32 
9 PCG - - - - - 13,18 
10 PCN - - 16,93 - - - 
11 PCT 31,16 - - - - - 
12 PDT -0,62 -0,76 -0,59 -0,26 0,23 0,00 
13 PEG - - - - - - 
14 PGC 1,55 -0,02 2,13 2,22 3,27 3,74 
15 PGD - 9,11 11,13 - - - 
16 PGS 2,04 1,85 4,61 3,83 52,32 4,25 
17 PIT 1,57 1,03 1,55 -0,13 -0,37 1,75 
18 PLX 1,34 4,11 11,72 4,22 4,78 4,56 
19 PMG 2,47 1,31 3,27 2,46 0,75 1,38 
20 PND 8,06 10,41 2,93 2,45 26,07 0,84 
21 POV 6,59 5,72 6,14 4,39 3,78 8,22 
22 PPY - - - - - 14,89 
23 PSC 2,15 2,62 2,68 2,56 2,14 1,77 
24 PTX -0,42 -0,20 -0,57 -0,79 -1,64 -1,01 
25 PVG 1,17 0,72 -0,11 0,00 0,27 3,92 
26 PVO 5,80 - 15,49 17,04 - - 
27 SFC 3,25 3,23 3,38 3,11 - 19,26 
28 TDG 1,91 6,77 6,00 5,22 4,31 2,40 
29 TLP 0,24 0,49 1,54 1,11 1,17 0,58 
30 TMC 28,46 6,76 77,64 4,84 5,05 6,48 
31 VMG 13,40 31,41 - -1,08 -0,30 -1,38 
Ghi chú: “-” thể hiện các DN thương mại dầu khí không sử dụng nợ vay