Dear All.,

I have the following dataset referring to daily observations for a bunch of US stocks:

Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
input float period double(apple microsoft ge gm wmt) float time
21551         155.214005          99.375191           7.709427          32.282429          91.487152 503
21552          139.75354          95.719376           7.719004          30.948524          91.016685 504
21553         145.719513         100.171211           7.881812          31.984938  91.58517499999999 505
21556 145.39520299999998         100.298965           8.370234 32.973372999999995          92.663338 506
21557          148.16687 101.02619899999999           8.197851 33.405215999999996          93.310226 507
21558         150.682983 102.47082499999999           8.140388          33.760281  93.00638599999999 508
21559         151.164627         101.812401  8.561772999999999 33.328441999999995          93.074997 509
21560         149.680466 101.02619899999999  8.561772999999999          35.679569          92.957375 510
21563 147.42971799999998         100.289146  8.523465999999999          36.140198          93.065193 511
21564         150.447128         103.198067  8.360657999999999          36.034637          94.339394 512
21565          152.28508         103.561684           8.600081          36.149792          94.437401 513
21566         153.189301         104.288918           8.753312          36.715981  94.81966399999999 514
21567         154.132858         105.851479           8.676696 37.051860999999995          95.790016 515
21571         150.673172         103.856506           8.293619          36.610424          95.554771 516
21572         151.282547         104.868729  8.360657999999999          36.149792          96.750557 517
21573 150.08343499999998         104.367531           8.408543          36.620022  96.40750899999999 518
21574         155.056747         105.320793  8.772466999999999          37.080647          95.015694 519
21577 153.62176499999998 103.26686099999999           8.552197          36.907909          95.133308 520
21578          152.02951         101.163788  8.523465999999999          36.917511  94.79025999999999 521
21579         162.418411         104.544426           8.715005          37.512493          92.918182 522
21580         163.587997         102.628075           9.730159          37.445313          93.927734 523
21581         163.666641         101.006546            9.75889          37.214996  91.99683399999999 524
21584         168.315582         103.915466           9.778043          37.358948          92.888756 525
21585         171.195389         105.369934          10.180275          37.714016          93.702293 526
21586 171.25436399999998          104.20047 10.027042999999999 38.299392999999995  93.74149299999999 527
21587          168.01091         103.453575            9.63439 37.090247999999995          94.809868 528
21588         168.208328 103.84667999999999           9.394966 37.138225999999996  93.68268599999999 529
21591 167.24096699999998         103.433922           9.605659          37.071056          94.290375 530
21592 168.68211399999998         105.045631           9.557775          37.454906  95.04510499999999 531
21593         167.981277 104.96700299999999           9.931274 37.426120999999995  95.99584999999999 532
21594         168.593292          105.05545           9.615235           37.32056          96.564323 533
21595         168.218201 106.35267599999999           9.663121          37.512493           98.00515 534
21599         168.721588 106.30354299999999           9.701428          37.934731         100.171272 535
21600         169.807388 105.75085399999999           9.672697 38.337779999999995          97.897331 536
21601          168.84993         107.981354           9.605659          38.021099  97.41706099999999 537
21602         170.735229         109.520973           9.739735 38.376166999999995          97.573875 538
21605         171.978958         110.132874          10.362236          38.520115  97.15241999999999 539
21606         172.077667         110.892822 10.617365999999999 38.491324999999996  96.73095699999999 540
21607 172.61068699999998         110.705299 10.836485999999999          38.385765  96.16246799999999 541
21608         170.912918 110.56713099999999          10.348446          37.886749  97.02499399999999 542
21609 172.70938099999998         111.060608          10.228926          37.934731          95.986038 543
21612         173.578033         110.794128          10.338485          37.666031          95.907623 544
21613         173.262161 110.24143199999999           9.850446           37.69482          96.387909 545
21614 172.26522799999998         110.290787           9.073564 37.109435999999995          96.309494 546
21615 170.27131699999998          108.94854           9.412205          36.867149  95.51557199999999 547
21616 170.67602499999998 109.06697799999999           9.551793          36.818687          95.652794 548
21619         176.588608 111.35668899999999           9.870851 37.429263999999996          96.525131 549
21620 178.57266199999998 112.13636799999999           9.731263 37.429263999999996          96.417313 550
21621 179.36231999999998         113.004875  9.990497999999999           37.60371  97.06420899999999 551
21622         181.356216 113.09369699999999          10.269673 36.857451999999995  96.78828399999999 552
21623         183.715332         114.396469  9.930674999999999          36.896217          96.985374 553
21626         185.590805 116.03478199999999          10.169967 36.808997999999995          98.207298 554
21627         184.120056 116.11374699999999          10.159996          37.090057          98.394531 555
21628 185.72898899999998 115.98544299999999          10.189909 35.859210999999995          97.202164 556
21629         192.569427 118.65019199999999          10.239761          36.198418          97.616035 557
21630          188.58165         115.521576  9.950614999999999          35.316479  96.84741199999999 558
21633         186.301483         116.123627           9.850909          35.616917          96.739014 559
21634         184.376678         116.370346          10.070262          35.733219  96.88681799999999 560
21635 186.03497299999998         115.245224  9.930674999999999 35.481235999999996  95.79300699999999 561
21636         186.281738         115.403145            9.86088          35.917366  95.71417199999999 562
21637 187.49586499999998         116.399963           9.960586 35.956126999999995          96.108345 563
21640 188.76921099999998         117.465858          10.070262          36.595779  96.39411199999999 564
21641 191.51328999999998         117.633636          10.209849          36.644238  95.52694699999999 565
21642         192.826111         118.403458          10.070262 37.206351999999995          95.773308 566
21643 193.16168199999998 117.80142199999999 10.000466999999999          37.594021          96.679886 567
21644         194.454758 118.32449299999999           9.980526          37.739395          97.389397 568
21647 197.51470899999998         118.363968           9.462057 37.855700999999996          97.783569 569
21648          196.92247          117.72245           9.192853          37.661865  97.25143399999999 570
21649         198.027985         118.620583            9.13303 38.039840999999996           98.14817 571
21650 196.37957799999998 118.75875099999999           9.093147          38.117371          99.330688 572
21651         196.300613         119.370651  8.973500999999999          38.485653          100.07959 573
21654          196.65596         119.469353           8.953559          38.349972          100.93692 574
21655         196.675705         119.193001           9.113089          38.437199         101.429626 575
21656         200.505585         120.179947           9.093147          38.757023 101.65628099999999 576
21657         201.226151         121.759056           9.322471          39.057465 101.67598699999999 577
21661         201.887497         122.143959  9.292558999999999          38.282131         100.877792 578
21662         204.799362         123.802032           9.302529          38.601959 101.56758099999999 579
21663 204.48350499999998         123.377647  9.292558999999999 38.495349999999995         102.020882 580
21664         202.627808         127.463577           9.093147          37.904156 102.01102399999999 581
21665         201.660461         128.193909  9.541820999999999          38.456585         100.050041 582
21668 201.96646099999998         128.075485            9.70135          38.776402          100.07959 583
21669         198.077362         128.894653          10.140055          37.749092         101.340942 584
21670          207.80011 126.21015899999999          10.070262 37.555251999999996          99.882515 585
21671           206.4478         124.561966           10.21982          37.070671          99.675575 586
21672         209.014221         127.216843 10.469083999999999           37.60371 100.59202599999999 587
21675 205.78646899999998         126.476624 10.399289999999999          36.915604         100.966476 588
21676 200.23907499999999         123.880966 10.080231999999999          37.342037  99.82339499999999 589
21677 200.27853399999998         123.871117          10.130085 37.031901999999995          98.837975 590
21678 198.12670899999998         123.861244 10.010437999999999          36.421329          98.610115 591
21679         195.381973         125.469955          10.100173          36.721771         100.957977 592
21682         184.026489         121.739311  9.840938999999999          35.432777          98.956841 593
21683         186.939667         123.101303          10.289614           35.89798          99.353104 594
21684         189.179062 124.83483899999999 10.229790999999999            36.2178           98.94693 595
21685         188.346725         127.717468          10.100173          36.227497         100.363571 596
21686         187.276581 126.86556999999999           9.970557 35.859210999999995  99.91778599999999 597
21689         181.420471         125.032967           9.850909 35.830138999999996         100.571609 598
21690 184.89846799999998 125.70657299999999  9.930674999999999          35.985203 100.17536199999999 599
21691         181.113281 126.46932199999999           9.870851          34.453918         101.274986 600
21692 178.02174399999998 124.99333999999999  9.531851999999999          34.046867          100.90844 601
21693         177.338043         125.052765           9.422175          34.037178         101.710869 602
21697         176.604782         124.973534           9.332441          33.775497         101.463211 603
21698         175.762527 123.76499899999999            9.34241 33.717349999999996         101.166016 604
21699         176.674149         124.547562           9.442117          33.746429 101.23535899999999 605
21700         173.473602         122.516846           9.412205 32.312056999999996         100.492363 606
21703         171.719727         118.712952           9.501939 32.660956999999996 101.00750699999999 607
21704         178.001923          122.00174           9.970557 34.628364999999995 101.60189799999999 608
21705 180.87545799999998 124.64662899999999            9.86088          34.734978         103.444519 609
21706         183.531036 126.61791199999999           9.890792          34.470497         104.128075 610
21707         188.416077          130.16423  9.950614999999999          34.764362         105.069199 611
21710         190.823929 131.35296599999998 10.020408999999999          35.273727         106.515564 612
21711         193.033585         130.857666 10.090202999999999          35.459846         106.931648 613
21712          192.41925         130.253403          10.249732          34.940681         107.803421 614
21713         192.379593         131.075592          10.279644          35.283524          107.63501 615
21714 190.98246799999998         131.204376          10.199878 34.930884999999996         108.051086 616
21717 192.12197899999998         131.600616 10.020408999999999           35.40107 108.14025099999999 617
21718 196.64039599999998         133.888885          10.389319 35.949622999999995         108.625671 618
21719         196.065689          134.41391          10.309555          36.027988 108.59595499999999 619
21720          197.64119 135.66203299999998          10.598701          36.204308         109.289406 620
21721         196.967377          135.68187          10.449142          36.165123         110.091843 621
21724 196.76921099999998         136.484238          10.249732          36.204308         110.200806 622
21725         193.786667          132.17514          10.189909 36.909583999999995         109.685677 623
21726 197.97808799999999 132.67044099999998          10.239761          37.350384 109.13091299999999 624
21727 197.91863999999998         132.888367          10.369378          37.536499 109.07146499999999 625
21728         196.115219          132.70018           10.47916 37.742202999999996 109.45781699999999 626
21731         199.712143         134.403992 10.608901999999999          37.957706         109.586609 627
21732         200.881363         135.295517          10.598922 37.556090999999995 110.55744899999999 628
21733 202.54605099999998         136.167252          10.588941 37.379771999999996         111.270721 629
21735         202.367676         135.771011           10.47916 37.712821999999996         110.933899 630
21738 198.19607499999998         135.671951          10.179755          37.448341         111.666985 631
21739         199.404968 135.17666599999998          10.229656          37.301407         111.825493 632
21740         201.376816         136.553604          10.179755          37.320999         111.924561 633
21741 199.91030899999998         137.098404          10.089933 37.644248999999995         112.855774 634
21742         201.446182         137.593704          10.349418          38.408302         113.529427 635
21745 203.33875999999998         137.593704 10.249616999999999          38.555237 113.90587599999999 636
21746         202.635223         135.790817          10.359399 38.623805999999995         113.687935 637
21747         201.495712         134.988449           9.960192          38.359325         113.529427 638
21748         203.784653         135.137039          10.040034          38.320141         113.648308 639
21749 200.74264499999998 135.33514399999999          10.020073 38.672782999999995         112.835968 640
21752 205.33042899999998 137.12811299999998 10.189734999999999           39.04501         111.766052 641
21753 206.93563799999998         137.980042 10.628860999999999          39.877632          111.04287 642
21754         206.767212         139.396591 10.658802999999999          40.044159 110.95371999999999 643
21755         205.132263         138.871582 10.409298999999999 39.916816999999995         111.171661 644
21756         205.845688 140.01075699999998          10.489141          39.936405         111.964188 645
21759          207.76799         139.703674          10.359399          39.848248 111.22119099999999 646
21760 206.87618999999998 139.03007499999998 10.499120999999999          39.603355 111.01315299999999 647
21761         211.097366         134.988449 10.429257999999999          39.515198         109.348846 648
21762         206.529373         136.761597          10.059994          39.329082 108.35818499999999 649
21763         202.159607         135.612503           9.980153          38.966648 108.37799799999999 650
21766         191.576981 130.96662899999998           9.640827          38.212387         104.831451 651
21767         195.203613         133.423309           9.551005          38.280964         106.267899 652
21768 197.22500599999998         134.007736           9.441224          38.584621 107.18920899999999 653
21769 201.57498199999998         137.583801           9.471164 39.280105999999996 108.03540799999999 654
21770 199.91392499999998         136.414917           9.131839          38.800125 106.80094899999999 655
21773         199.406647         134.512939           9.032038           38.06546         104.750153 656
21774         207.851212         137.296539           9.331443          38.212387         106.930374 657
21775         201.664505         133.161926           9.012077          36.429604         105.725769 658
21776         200.659912         132.863754           7.994102 35.724326999999995         112.186798 659
21777         205.394424         135.298813           8.772553          36.243488         112.485451 660
21780         209.223816         137.564896           8.652792 36.596129999999995         113.301788 661
21781 209.23376499999998         136.421906           8.363368          36.204308         111.549652 662
21782         211.501556 137.94255099999998           8.143805          36.361031 111.51978299999999 663
21783 211.32252499999998         136.938721           8.173744          36.498173 111.41027799999999 664
21784 201.55509899999998 132.57553099999998  7.954180999999999          35.322708 110.33509799999999 665
21787 205.38447599999998         134.622955           8.034023          35.508823         111.489914 666
21788         203.066956         134.911179           7.914261          35.156181         111.917999 667
21789 204.42962599999998         134.732269  7.924240999999999          35.694939 112.21665999999999 668
21790         207.890976 137.27664199999998           8.093904          36.155331 113.57058699999999 669
21791         207.622437          137.01825           8.233625 36.331649999999996         113.749786 670
21795         204.598694         135.209351           8.313467          36.155331 114.12808199999999 671
21796 208.07003799999998         136.789658           8.782535          37.458138 115.39241799999999 672
21797 212.13812299999998 139.19486999999998           8.792515          38.318901         114.924515 673
21798         212.118225 138.25067099999998           8.692713          38.368366 114.21768999999999 674
21801         213.023361         136.680328           8.942217          39.159878 115.81053899999999 675
21802          215.53981         135.249115            9.12186          39.159878         115.531792 676
21803 222.39292899999998         135.288849  9.341422999999999          39.041149 115.50192299999999 677
21804 221.89559899999998         136.680328           9.241622          38.655293         116.397903 678
21805 217.57884199999998         136.481537            9.33154 38.447520999999995         116.905632 679
21808 218.72268699999998         135.497589           9.371504          36.815033 115.05393199999999 680
21809 219.51840199999998         136.551117           9.351521          37.883572 115.98973799999999 681
21810 221.57733199999998          137.67421           9.371504          37.774738 116.63684099999999 682
21811 219.77702299999999 140.20864899999998           9.411468          37.378983         116.587059 683
21812 216.56428499999998         138.588593           9.361512          36.973335 116.45764199999999 684
21815         217.548996 138.29042099999998            9.33154          36.844719          117.09478 685
21816         216.514557         136.541183           8.961875          36.379704 117.87129999999999 686
21817         219.846634 138.50907899999999           9.151703 36.716094999999996 117.94098699999999 687
21818         218.712738         138.687973            9.01183          37.210789         117.771744 688
21819         217.648483 136.88902299999998           9.031812          37.022804 117.92107399999999 689
21822 222.77088899999998 138.18109099999998           8.931902          37.082169         118.150047 690
21823         223.387573         136.233078  8.602200999999999          35.726711         117.323753 691
21824 217.78771999999998         133.827835  8.502291999999999           34.31189         115.601479 692
21825         219.637756         135.447891            8.70211 34.608703999999996         115.790627 693
21826         225.794617 137.27664199999998           8.562237          34.539448          117.63237 694
21829 225.84434499999998         136.282761           8.552247          34.381145 116.70652799999999 695
21830         223.198593         134.841614  8.272499999999999          33.520382 117.05496199999999 696
21831         225.814514          137.39592           8.342437          33.777618         118.398933 697
21832         228.858124 138.25067099999998  8.442345999999999          34.292099         119.075897 698
21833         234.945358 138.82711799999998           8.792029           35.19244 119.70307899999999 699
21836 234.60717799999998         138.697922           8.712102          35.123184         118.637856 700
21837         234.060135 140.70559699999998           8.881948 35.875113999999996         118.996246 701
21838 233.11520399999998         139.552673           8.891938          36.260979         118.886742 702
21839 234.02033999999998         138.837067           9.031812          35.805859         119.304863 703
21840 235.14430199999998 136.57098399999998           8.951884          35.786072 118.60799399999999 704
21843 239.22233599999998         137.584747           8.782038          35.548622 119.20530699999999 705
21844 238.67529299999998         135.537338           9.051794 35.924586999999995 119.04602799999999 706
21845 241.87803599999998         136.402039  9.131720999999999          36.221405         118.817055 707
21846         242.275894         139.085556           8.941893          35.439789         118.568169 708
21847         245.259842         139.870712           8.991848 36.350024999999995         118.508438 709
21850         247.716614         143.309601           9.061784          36.251083         118.687637 710
21851         241.987442         141.957901           9.061784          37.804417         116.626877 711
21852 241.95761099999999         143.727036          10.100842 37.507602999999996         117.572632 712
21853         247.428162         142.494583            9.97096          36.765564 116.73638899999999 713
21854         254.450378         142.842468          10.370598          37.566967          117.09478 714
21857 256.12136799999996         143.667404            10.9201           37.98251         117.045006 715
21858 255.75337199999998         143.577957          10.960064          37.824207         118.329247 716
21859 255.86276199999998         143.180374 11.010017999999999 38.012187999999995 118.96638499999999 717
21860 258.81573499999996 143.37914999999998          11.279774          38.081448          119.69313 718
21861         259.524078         145.068787          11.509565          38.259537 118.90665399999999 719
21864         261.579193         145.217865           11.33972          38.309006         118.508438 720
21865         261.339752         146.172012          11.409656          38.180386 118.58808099999999 721
21866 263.84381099999996         146.410538          11.279774          36.795246         120.439781 722
21867 262.01815799999997          147.15596          11.279774          36.409386         120.111252 723
21868         265.130768         149.054306          11.509565          36.498428         118.339203 724
21871          266.46759         149.422043          11.429637          36.231297 119.71303599999999 725
21872         265.659515         149.471725          11.489583 35.993846999999995 119.35464499999999 726
21873         262.566864         149.212433          11.379683          34.905518 118.59803799999999 727
21874 261.38964799999997         149.072815          11.519556          34.301994         119.324776 728
21875         261.160187         149.182526          11.539538 34.954989999999995         118.827011 729
21878 265.73931899999997         150.818054           11.56951          35.429897 118.38896899999999 730
21879         263.664246         151.615875           11.33972          35.528831 118.65776799999999 731
21880 267.20584099999996          151.90509          11.279774 35.756389999999996 118.22969099999999 732
21882         266.617249         150.967651          11.259792          35.617878         118.558212 733
21885         263.534546         149.142639          11.149891          35.499153         118.747368 734
21886 258.83572399999997          148.90329 10.980044999999999 35.152865999999996         118.140091 735
21887          261.12027 149.44181799999998 10.890125999999999          35.419998         118.160004 736
21888         264.951172         149.521591          10.780227          35.310001         118.660004 737
21889         270.069031         151.336639          11.089946          35.540001 119.77999899999999 738
21892         266.288025         150.947708 10.980044999999999          35.380001         119.360001 739
21893          267.84433         150.718338          11.000028          35.110001 119.13999899999999 740
21894         270.128906 151.28677399999998          10.960064          35.240002                119 741
21895         270.817261         152.822586          11.429637          36.099998         119.760002 742
21896         274.498535          154.10907          11.329728          35.650002 120.29000099999999 743
21899         279.197357         155.106339 11.159882999999999          36.110001 120.54000099999999 744
21900 279.74609399999997         154.268631          11.089946          36.310001 121.27999899999999 745
21901 279.07766699999996         153.949509 10.950071999999999          37.310001         119.860001 746
21902         279.356995         155.285858              11.03 37.259997999999996         120.080002 747
21903 278.77838099999997         156.981232              11.03              37.25 120.29000099999999 748
21906 283.32757599999997         156.981232              11.16 36.769999999999996 119.02999899999999 749
21907         283.596924 156.95130899999998              11.19          36.580002         119.510002 750
21909 289.22360199999997 158.23779299999998 11.229999999999999              36.48 119.51999699999999 751
21910         289.113831         158.527008              11.18          36.560001         119.589996 752
21913         290.829773 157.16073599999999              11.08          36.439999         119.400002 753
21914         292.954712         157.270432              11.16          36.599998         118.839996 754
end
format %td period
I would like to test cointegration among all the possible pairs. Having 5 stocks all the possible combinations (excluding a stock with itself and any repetitions, i.e. apple and microsoft and microdoft and apple) are 10. Below is an example of the code I would like to run for each pair (the example is between apple and microsoft).

Code:
tsset time
reg L(0/2).apple L(1/2).microsoft
testparm L(1/2).microsoft
reg L(0/2).microsoft L(1/2).apple
testparm L(1/2).apple
reg apple microsoft
predict res_apple_microsoft, res
dfuller res_apple_microsoft, nocon
I tried to figure out any possible loop which can allow me to run quickly the code above for all possible pairs, but unfortunately I was not able to do so. Does someone have any suggestion? Thanks in advance.

Dario