Thanks for reading my post. I have a series of portfolios created from the combination of several stocks. I should compute the volatility of those portfolios using the historical daily performances of each stock. Since I have all the combinations in one data frame (called final_output), and all stocks return in another data frame (called perf, where the columns are stocks and rows days) I don't know which will be the most efficient way to automize the process. Below you can find an extract:
> Final_output
ISIN_1 ISIN_2 ISIN_3 ISIN_4
2 CH0595726594 CH1111679010 XS1994697115 CH0587331973
3 CH0595726594 CH1111679010 XS1994697115 XS2027888150
4 CH0595726594 CH1111679010 XS1994697115 XS2043119358
5 CH0595726594 CH1111679010 XS1994697115 XS2011503617
6 CH0595726594 CH1111679010 XS1994697115 CH1107638921
7 CH0595726594 CH1111679010 XS1994697115 XS2058783270
8 CH0595726594 CH1111679010 XS1994697115 JE00BGBBPB95
> perf
CH0595726594 CH1111679010 XS1994697115 CH0587331973
626 0.0055616769 -0.0023656130 1.363791e-03 1.215922e-03
627 0.0086094443 0.0060037334 0.000000e+00 2.519220e-03
628 0.0053802380 0.0009027081 0.000000e+00 7.508635e-04
629 -0.0025213543 -0.0022046297 4.864050e-05 1.800720e-04
630 0.0192416817 0.0093401627 -6.079767e-03 3.800836e-03
631 -0.0101224820 0.0051741294 6.116956e-03 -1.345184e-03
632 -0.0013293793 -0.0100475153 -4.494163e-03 -1.746106e-03
633 0.0036350604 0.0012999350 3.801130e-03 -5.997121e-05
634 0.0030097434 -0.0011484496 -1.187614e-03 -2.069131e-03
635 0.0002034381 0.0030493901 -1.851762e-03 -3.806280e-04
636 -0.0035594427 0.0167455769 -2.148123e-04 -4.709560e-04
637 0.0007654623 -0.0051958237 -3.711191e-04 1.604010e-04
638 0.0107592678 -0.0016260163 4.298764e-04 3.397951e-03
639 0.0050953486 -0.0007403020 2.011738e-03 8.790770e-04
640 0.0008532851 -0.0071121648 -9.746114e-04 5.389598e-04
641 -0.0068204614 0.0133810874 -9.755622e-05 -1.346674e-03
642 0.0091395678 0.0102591793 1.717157e-03 -1.977785e-03
643 0.0027520640 -0.0157912638 1.256440e-03 -1.301119e-04
644 -0.0048902196 0.0039494471 -1.624514e-03 -3.373340e-03
645 -0.0116838833 0.0062450826 6.625549e-04 1.205255e-03
646 0.0004566442 -0.0018570102 -3.456636e-03 4.474138e-03
647 0.0041586368 0.0085679315 4.435933e-03 1.957455e-03
648 0.0007575758 0.0002912621 0.000000e+00 2.053306e-03
649 0.0046429473 -0.0138309230 -4.435798e-03 1.541798e-03
650 0.0049731250 -0.0488164953 4.181975e-03 -9.733133e-04
651 0.0008497451 -0.0033110870 2.724477e-04 -7.555498e-04
652 0.0004494831 0.0049831300 -8.657588e-04 -1.790813e-04
653 -0.0058905751 0.0020143588 8.178287e-04 -1.213991e-03
654 0.0000000000 0.0167525773 4.864050e-05 9.365068e-04
655 0.0010043186 0.0048162231 0.000000e+00 -2.110146e-03
656 -0.0024079462 -0.0100403633 -2.431907e-03 -9.176600e-04
657 -0.0095544604 -0.0193670047 0.000000e+00 -8.935435e-03
658 0.0008123477 0.0114339172 2.437835e-03 5.530483e-03
659 0.0022828734 -0.0015415446 -3.239300e-03 2.765060e-03
660 0.0049096523 -0.0001029283 3.199079e-02 2.327835e-03
661 -0.0027702226 -0.0357198003 9.456712e-04 3.189602e-04
662 -0.0008081216 -0.0139311449 -2.891020e-02 -1.295363e-03
663 -0.0033867462 0.0068745264 -2.529552e-03 -1.496588e-04
664 -0.0015216068 -0.0558572120 -3.023653e-03 -7.992975e-03
665 0.0052829422 0.0181072771 4.304652e-03 -3.319519e-03
666 0.0084386054 0.0448545861 -8.182748e-04 4.279284e-03
667 -0.0076664829 -0.0059415480 -2.047362e-04 6.059936e-03
668 -0.0062108665 -0.0039847073 7.313506e-04 5.993467e-04
669 -0.0053350948 0.0068119154 -1.042631e-02 -2.056524e-03
670 -0.0263588067 0.0245395479 -2.188962e-02 -6.732491e-03
671 -0.0021511018 0.0220649895 1.412435e-02 1.702085e-03
672 0.0205058100 -0.0007179119 3.057527e-03 -1.002423e-02
673 0.0096862280 -0.0194488633 1.207407e-03 -1.553899e-03
674 0.0007143951 -0.0068557672 6.227450e-03 1.790274e-03
675 -0.0021926470 -0.0051114507 -6.267498e-03 -1.035691e-03
676 0.0076655765 -0.0139300847 6.583825e-03 3.059472e-03
677 -0.0032457653 0.0180480206 -4.635495e-03 1.064002e-03
678 0.0036633764 0.0060676410 -2.762676e-04 5.364970e-04
679 -0.0008111122 -0.0013635410 -1.065898e-03 1.214059e-03
680 0.0050228311 0.0055141267 3.003507e-03 1.121643e-03
681 -0.0007067495 0.0147281558 -2.699002e-03 -1.514035e-04
682 -0.0024248548 0.0002573473 -2.113685e-03 -1.423409e-03
683 -0.0002025624 0.0138417207 -4.374895e-03 1.415328e-04
684 -0.0141822418 -0.0169517332 -3.578920e-03 -1.799234e-03
685 -0.0005651749 -0.0259693324 -5.926428e-03 -3.635333e-03
686 0.0004112688 0.0133043570 -1.545642e-03 1.981828e-03
687 -0.0150565262 -0.0107757493 -1.717916e-02 -1.328749e-02
688 0.0039129754 -0.0441013167 -8.376631e-03 -5.653841e-04
689 0.0019748467 0.0115063340 -2.835394e-02 7.868428e-03
690 0.0072614108 0.0358764014 3.586897e-02 7.960077e-03
691 -0.0003604531 0.0106119001 1.024769e-04 -2.733651e-04
What I should do is look for each portfolio (each row of final_output is a portfolio, i.e. 4 stocks portfolio) in perf and compute the volatility (standard deviation) of that portfolio using the stocks historical daily performances of the last three months. (Of course, here I have pasted only 4 stocks performances for simplicity.) Once done for the first, I should do the same for all the other rows (portfolios).
Below is the formula I used for computing the volatility:
#formula for computing the volatility
sqrt(t(weights) %*% covariance_matrix %*% weights)
#where covariance_matrix is
cov(portfolio_component_monthly_returns)
#All the portfolios are equiponderated
weights = [ 0.25 0.25 0.25 0.25 ]
What I'm trying to do since yesterday is to automize the process for all the rows, indeed I have more than 10'000 rows. I'm an RStudio naif, so even trying and surfing on the new I have no results and no ideas of how to automize it. Would someone have a clue how to do it?
Hope to have been clearer as possible, in case do not hesitate to ask me.
Many thanks
