[R-SIG-Finance] [R-sig-finance] Garch problem

RON70 ron_michael70 at yahoo.com
Tue Mar 17 11:27:38 CET 2009


I have following dataset as monthly percentage return for a stock :

0.173741362
-0.062237174
0.02690583
0.04628821
0.056761269
0.018167457
-0.003103181
0.024902724
0.035687168
0.004398827
-0.054014599
-0.141975309
0.008093525
-0.035682426
0.034227567
-0.072450805
-0.037608486
0.026052104
-0.055664062
-0.024819028
-0.004241782
-0.052183174
-0.004494382
0.081828442
-0.015127804
0.091101695
-0.027184466
-0.032934132
-0.012383901
-0.009404389
0.033755274
-0.004081633
-0.014344262
0.033264033
0.03722334
0.094083414
0.019503546
0.010434783
-0.003442341
-0.121761658
0.041297935
0.050991501
-0.056603774
-0.018095238
0.022308438
-0.059772296
0.042381433
0.012584705
0.003824092
-0.024761905
0.047851562
-0.018173346
0.034646417
-0.033027523
-0.007590133
-0.004780115
0.008645533
-0.016190476
-0.016456922
0.049212598
0.003752345
-0.008411215
0.100848256
0.042808219
0.063218391
-0.016602317
0.056144484
0.054275093
0.028208745
0.020576132
-0.092741935
-0.061481481
-0.08445146
-0.045689655
0.023486902
-0.064430715
0.037735849
0.001818182
-0.025408348
-0.049348231
0.065621939
-0.054227941
-0.040816327
-0.038500507
0.062170706
-0.074404762
0.046087889
0.079918033
-0.046489564
0.080597015
-0.092081031
0.059837728
0.041148325
0.098345588
0.007531381
-0.039036545
0.021607606
0.044839255
-0.07611336
-0.043821209
0.028414299
0.041889483
-0.026518392
0.013181019
0.01300954
0.010273973
-0.022033898
-0.066291161
-0.011600928
-0.020187793
0.00431241
-0.014312977
-0.039690223
-0.023185484
-0.036119711
-0.042826552
-0.035234899
-0.016231884
-0.063052445
-0.031446541
0.045454545
-0.021118012
0.007614213
0.023929471
0.036900369
-0.024911032
-0.0486618
0.051150895
-0.057177616
0.010322581
-0.029374202
0.044736842
0.042821159
-0.073671498
0.070404172
-0.004872107
-0.048959608
0.009009009
0.00127551
0.01910828
0.09
-0.055045872
0.024271845
0.146919431
-0.013429752
0.064921466
0.025565388
0.091083413
-0.024604569
-0.06036036
0.064237776
-0.106306306
0.050403226
-0.065259117
0.137577002
-0.040613718
0.100658514
0.064957265
0.040930979
0.070932922
-0.010079194
-0.055272727
-0.010777521
-0.042801556
0.028455285
0.079841897
0.039531479
0.088028169
0.110032362
0.113119534
0.207962284
0.022983521
0.121237813
0.200378072
0.155905512
-0.122615804
0.060559006
0.010248902
-0.034782609
0.267267267
0.036729858
-0.033142857
-0.177304965
0
-0.064655172
0.153917051
-0.016240682
-0.093369418
0.058208955
-0.122708039
-0.019292605
-0.073770492
-0.081415929
-0.086705202
0.061181435
0.089463221
-0.153284672
-0.038793103
-0.100896861
-0.036408978
-0.01552795
-0.047844374
-0.072335726
-0.330357143
0.075555556
-0.001652893
-0.092301325

Now I fit a GARCH (1,1) model on that :

> garch(Delt(dat)[-1], c(1,1))

 ***** ESTIMATION WITH ANALYTICAL GRADIENT ***** 


     I     INITIAL X(I)        D(I)

     1     4.331103e-03     1.000e+00
     2     5.000000e-02     1.000e+00
     3     5.000000e-02     1.000e+00

    IT   NF      F         RELDF    PRELDF    RELDX   STPPAR   D*STEP  
NPRELDF
     0    1 -4.507e+02
     1    6 -4.508e+02  2.00e-04  3.20e-04  1.5e-03  6.3e+06  1.5e-04 
1.01e+03
     2    7 -4.508e+02  1.57e-05  1.69e-05  1.4e-03  2.0e+00  1.5e-04 
3.19e-01
     3   13 -4.521e+02  2.85e-03  4.72e-03  5.6e-01  2.0e+00  1.3e-01 
3.16e-01
     4   16 -4.602e+02  1.76e-02  4.41e-03  8.1e-01  6.7e-01  5.1e-01 
1.99e-02
     5   23 -4.607e+02  1.13e-03  2.77e-03  1.6e-04  7.4e+00  1.8e-04 
8.48e+00
     6   24 -4.607e+02  4.81e-05  4.37e-05  1.6e-04  2.0e+00  1.8e-04 
1.77e+01
     7   30 -4.638e+02  6.60e-03  8.81e-03  9.8e-02  2.0e+00  1.2e-01 
1.84e+01
     8   31 -4.645e+02  1.52e-03  7.73e-03  8.2e-02  1.3e+00  1.2e-01 
1.39e-02
     9   33 -4.688e+02  9.18e-03  6.28e-03  6.8e-02  0.0e+00  1.2e-01 
6.94e-03
    10   35 -4.693e+02  9.32e-04  9.33e-04  8.9e-03  1.9e+00  1.8e-02 
2.86e-02
    11   37 -4.699e+02  1.34e-03  1.59e-03  1.6e-02  1.8e+00  3.5e-02 
5.99e-02
    12   38 -4.704e+02  1.05e-03  1.43e-03  1.6e-02  1.6e+00  3.5e-02 
9.10e-03
    13   40 -4.705e+02  1.84e-04  2.85e-04  5.3e-03  1.2e+00  1.3e-02 
7.52e-04
    14   42 -4.705e+02  3.71e-05  5.18e-05  2.4e-03  8.1e-01  5.0e-03 
7.09e-05
    15   44 -4.705e+02  8.51e-07  3.04e-06  4.9e-04  8.2e-01  9.5e-04 
5.29e-06
    16   57 -4.705e+02 -7.73e-15  1.09e-15  5.0e-15  4.4e+06  9.1e-15 
2.87e-07

 ***** FALSE CONVERGENCE *****

 FUNCTION    -4.704848e+02   RELDX        4.961e-15
 FUNC. EVALS      57         GRAD. EVALS      16
 PRELDF       1.088e-15      NPRELDF      2.867e-07

     I      FINAL X(I)        D(I)          G(I)

     1    2.824235e-05     1.000e+00     5.619e+01
     2    8.649332e-02     1.000e+00    -5.899e-01
     3    9.175397e-01     1.000e+00    -6.866e-01


Call:
garch(x = Delt(dat)[-1], order = c(1, 1))

Coefficient(s):
       a0         a1         b1  
2.824e-05  8.649e-02  9.175e-01  

Warning message:
In sqrt(pred$e) : NaNs produced

What we see that sum of alpha and beta coef is more than 1. Therefore
probably I choose a wrong model on my dataset. Can anyone please guide me
how to modify that model?

Regards,
-- 
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