Figure 1

Descriptive statistics of six European stock index prices (for the period 2008–2018)
| DAX | FTSE 100 | CAC 40 | FTSE MIB | MDAX | IBEX 35 | |
|---|---|---|---|---|---|---|
| Mean | 59.60722 | 21.86251 | 72.62883 | 16.02681 | 67.01549 | 25.12312 |
| Median | 58.14654 | 19.65725 | 73.66524 | 17.49506 | 68.14011 | 26.01219 |
| SD | 14.85281 | 2.105744 | 7.065241 | 2.625164 | 6.056982 | 1.991045 |
| Skewness | 0.565189 | –0.251102 | –0.265694 | –0.414151 | –0.112697 | 0.215631 |
| Kurtosis | 4.159295 | 3.056694 | 1.952011 | 2.622373 | 3.124191 | 3.018854 |
| Jarque-Bera | 15.19295 | 4.960236 | 2.968939 | 6.409951 | 4.165313 | 8.456301 |
| Probability | 0.000152 | 0.000294 | 0.000621 | 0.000657 | 0.000219 | 0.000806 |
| No. of companies | 30 | 100 | 40 | 40 | 60 | 35 |
| Observations | 3,025 | 3,025 | 3,025 | 3,025 | 3,025 | 3,025 |
The results of risk level (diversification benefits) linked with the six different portfolios
| Years | Portfolio (A) DAX | Portfolio (B) FTSE100 | Portfolio (C) CAC40 | Portfolio (E) FTSE MIB | Portfolio (F) MDAX | Portfolio (G) IBEX35 | All Portfolios (ABCEFG) |
|---|---|---|---|---|---|---|---|
| 2008 | 1.83 | 0.23 | 1.38 | 0.21 | 2.35 | 0.37 | 0.33 |
| 2009 | 4.86 | 0.85 | 3.68 | 0.95 | 7.05 | 0.94 | 1.45 |
| 2010 | 2.89 | 0.47 | 3.04 | 0.82 | 3.34 | 1.13 | 1.12 |
| 2011 | 1.48 | 0.19 | 1.17 | 0.28 | 2.41 | 0.42 | 0.42 |
| 2012 | 3.33 | 0.25 | 3.10 | 0.73 | 3.80 | 0.57 | 0.88 |
| 2013 | 1.66 | 0.19 | 1.34 | 0.29 | 1.35 | 0.50 | 0.82 |
| 2014 | 1.89 | 0.21 | 2.02 | 0.32 | 1.10 | 0.49 | 0.50 |
| 2015 | 1.12 | 0.18 | 0.94 | 0.22 | 1.44 | 0.33 | 0.27 |
| 2016 | 2.95 | 0.41 | 2.05 | 0.33 | 2.16 | 0.48 | 0.61 |
| 2017 | 1.40 | 0.21 | 1.72 | 0.36 | 1.89 | 0.31 | 0.51 |
| 2018 | 1.61 | 0.12 | 1.83 | 0.37 | 2.33 | 0.39 | 0.36 |
Average risk and return tradeoffs for different poolings of the portfolios (stock indexes), 2008–2018
| Portfolios | Stock indexes | Omega, average | SD, average | Correlation coefficient, average | No. of stock indexes | WAR (%) | No. of stocks |
|---|---|---|---|---|---|---|---|
| Portfolio (AB) | DAX + FTSE100 | 0.69 | 3.04 | 0.30 | 2 | 6.33 | 129 |
| Portfolio (AC) | DAX + CAC40 | 2.17 | 4.65 | 0.42 | 2 | 0.17 | 70 |
| Portfolio (AE) | DAX + FTSE MIB | 0.87 | 3.22 | 0.40 | 2 | 0.56 | 69 |
| Portfolio (AF) | DAX + MDAX | 2.26 | 4.65 | 0.41 | 2 | 0.08 | 77 |
| Portfolio (AG) | DAX + IBEX35 | 0.96 | 3.66 | 0.39 | 2 | 0.05 | 62 |
| Portfolio (BC) | FTSE100 + CAC40 | 0.64 | 2.89 | 0.27 | 2 | 6.30 | 139 |
| Portfolio (BE) | FTSE100 + FTSE MIB | 0.52 | 2.19 | 0.26 | 2 | 5.12 | 138 |
| Portfolio (BF) | FTSE100 + MDAX | 0.56 | 2.96 | 0.26 | 2 | 7.11 | 146 |
| Portfolio (BG) | FTSE100 + IBEX35 | 0.47 | 2.27 | 0.26 | 2 | 4.95 | 131 |
| Portfolio (CE) | CAC40 + FTSE MIB | 0.91 | 3.09 | 0.42 | 2 | 0.96 | 79 |
| Portfolio (CF) | CAC40 + MDAX | 2.03 | 4.34 | 0.42 | 2 | 0.04 | 87 |
| Portfolio (CG) | CAC40 + IBEX35 | 0.85 | 3.28 | 0.42 | 2 | 0.03 | 72 |
| Portfolio (EF) | FTSE MIB + MDAX | 0.59 | 3.12 | 0.38 | 2 | 0.67 | 86 |
| Portfolio (EG) | FTSE MIB + IBEX35 | 0.58 | 1.93 | 0.38 | 2 | 0.66 | 71 |
| Portfolio (FG) | MDAX + IBEX35 | 0.59 | 3.45 | 0.35 | 2 | 0.00 | 79 |
| Portfolio (ABC) | DAX + FTSE100 + CAC40 | 0.78 | 3.32 | 0.30 | 3 | 5.67 | 169 |
| Portfolio (ABE) | DAX + FTSE100 + FTSEMIB | 0.64 | 2.77 | 0.28 | 3 | 4.73 | 168 |
| Portfolio (ABF) | DAX + FTSE100 + MDAX | 0.70 | 3.38 | 0.29 | 3 | 6.32 | 168 |
| Portfolio (ABG) | DAX + FTSE100 + IBEX35 | 0.60 | 2.85 | 0.28 | 3 | 4.55 | 161 |
| Portfolio (ACE) | DAX + CAC40 + FTSE MIB | 1.14 | 3.71 | 0.40 | 3 | 0.87 | 109 |
| Portfolio (ACF) | DAX + CAC40 + MDAX | 2.16 | 4.58 | 0.41 | 3 | 0.17 | 117 |
| Portfolio (ACG) | DAX + CAC40 + IBEX35 | 1.14 | 3.88 | 0.41 | 3 | 0.03 | 102 |
| Portfolio (AEF) | DAX + FTSEMIB + MDAX | 0.89 | 3.66 | 0.39 | 3 | 0.57 | 101 |
| Portfolio (AEG) | DAX + FTSEMIB + IBEX35 | 0.79 | 2.99 | 0.37 | 3 | 0.62 | 101 |
| Portfolio (AFG) | DAX + MDAX + IBEX35 | 0.99 | 3.99 | 0.38 | 3 | 0.07 | 109 |
| Portfolio (BCE) | FTSE100 + CAC40 + FTSE MIB | 0.60 | 2.67 | 0.27 | 3 | 4.72 | 178 |
| Portfolio (BCF) | FTSE100 + CAC40 + MDAX | 0.65 | 3.24 | 0.27 | 3 | 6.29 | 186 |
| Portfolio (BCG) | FTSE100 + CAC40 + IBEX35 | 0.57 | 2.74 | 0.27 | 3 | 4.54 | 171 |
| Portfolio (BEF) | FTSE100 + FTSE MIB + MDAX | 0.53 | 2.73 | 0.26 | 3 | 4.25 | 185 |
| Portfolio (BEG) | FTSE100 + FTSE MIB + IBEX35 | 0.48 | 2.16 | 0.25 | 3 | 3.99 | 170 |
| Portfolio (BFG) | FTSE100 + MDAX + IBEX35 | 0.49 | 2.80 | 0.26 | 3 | 4.96 | 178 |
| Portfolio (CEF) | CAC40 + FTSE MIB + MDAX | 0.93 | 3.57 | 0.40 | 3 | 0.96 | 126 |
| Portfolio (CEG) | CAC40 + FTSE MIB + IBEX35 | 0.73 | 2.79 | 0.41 | 3 | 0.58 | 111 |
| Portfolio (CFG) | CAC40 + MDAX + IBEX35 | 0.89 | 3.72 | 0.40 | 3 | 0.00 | 119 |
| Portfolio (EFG) | FTSE MIB + MDAX + IBEX35 | 0.60 | 2.91 | 0.36 | 3 | 0.67 | 118 |
| Portfolio (ABCE) | DAX + FTSE100 + CAC40 + FTSEMIB | 0.71 | 3.06 | 0.29 | 4 | 4.39 | 208 |
| Portfolio (ABCF) | DAX + FTSE100 + CAC40 + MDAX | 0.79 | 3.53 | 0.29 | 4 | 5.67 | 216 |
| Portfolio (ABCG) | DAX + FTSE100 + CAC40 + IBEX35 | 0.69 | 3.13 | 0.29 | 4 | 4.21 | 201 |
| Portfolio (ABEF) | DAX + FTSE100 + FTSE MIB + MDAX | 0.65 | 3.11 | 0.28 | 4 | 4.75 | 215 |
| Portfolio (ABEG) | DAX + FTSE100 + FTSEMIB + IBEX35 | 0.58 | 2.66 | 0.284 | 4 | 3.75 | 200 |
| Portfolio (ABFG) | DAX + FTSE100 + MDAX + IBEX35 | 0.61 | 3.18 | 0.287 | 4 | 0.87 | 208 |
| Portfolio (ACEF) | DAX + CAC40 + FTSEMIB + MDAX | 1.16 | 3.92 | 0.39 | 4 | 0.55 | 141 |
| Portfolio (ACEG) | DAX + CAC40 + FTSE MIB + IBEX35 | 0.90 | 3.35 | 0.39 | 4 | 4.57 | 141 |
| Portfolio (ACFG) | DAX + CAC40 + MDAX + IBEX35 | 1.16 | 4.04 | 0.39 | 4 | 0.05 | 149 |
| Portfolio (AEFG) | DAX + FTSEMIB + MDAX + IBEX35 | 0.81 | 3.43 | 0.36 | 4 | 0.63 | 148 |
| Portfolio (BCEF) | FTSE100 + CAC40 + FTSEMIB + MDAX | 0.61 | 3.01 | 0.27 | 4 | 4.74 | 225 |
| Portfolio (BCEG) | FTSE100 + CAC40 + FTSEMIB + IBEX35 | 0.55 | 2.57 | 0.27 | 4 | 3.74 | 210 |
| Portfolio (BCFG) | FTSE100 + CAC40 + MDAX + IBEX35 | 0.58 | 3.07 | 0.27 | 4 | 0.59 | 218 |
| Portfolio (BEFG) | FTSE100 + FTSE MIB + MDAX + IBEX35 | 0.49 | 2.63 | 0.26 | 4 | 4.01 | 217 |
| Portfolio (CEFG) | CAC40 + FTSEMIB + MDAX + IBEX35 | 0.75 | 3.26 | 0.39 | 4 | 3.74 | 158 |
| Portfolio (ABCEF) | DAX + FTSE100 + CAC40 + FTSEMIB + MDAX | 0.72 | 3.28 | 0.29 | 5 | 4.41 | 255 |
| Portfolio (ABCEG) | DAX + FTSE100 + CAC40 + FTSE MIB + IBEX35 | 0.65 | 2.92 | 0.29 | 5 | 3.53 | 240 |
| Portfolio (ABCFG) | DAX + FTSE100 + CAC40 + MDAX + IBEX35 | 0.69 | 3.35 | 0.29 | 5 | 4.24 | 248 |
| Portfolio (ABEFG) | DAX + FTSE100 + FTSEMIB + MDAX + IBEX35 | 0.59 | 2.97 | 0.28 | 5 | 3.77 | 247 |
| Portfolio (ACEFG) | DAX + CAC40 + FTSEMIB + MDAX + IBEX35 | 0.92 | 3.60 | 0.38 | 5 | 0.57 | 188 |
| Portfolio (BCEFG) | FTSE100 + CAC40 + FTSEMIB + MDAX + IBEX35 | 0.56 | 2.89 | 0.27 | 5 | 0.66 | 257 |
Risk elements of the individual stock indexes
| Portfolios | 2008 | 2009 | 2010 | 2011 | 2012 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| std-FTSE100 | 1.15 | 1.43 | 0.98 | 0.82 | 0.91 | 1.03 | 1.11 | 1.20 | 1.77 | 1.68 | 1.44 |
| std-CAC40 | 3.32 | 5.72 | 4.31 | 2.91 | 3.92 | 3.35 | 3.75 | 3.22 | 4.89 | 4.60 | 5.80 |
| std-DAX | 4.23 | 7.91 | 4.69 | 3.79 | 4.71 | 3.87 | 4.59 | 3.64 | 6.94 | 5.39 | 5.14 |
| std-IBEX35 | 2.08 | 3.61 | 1.53 | 1.27 | 1.58 | 2.91 | 1.39 | 1.15 | 1.60 | 1.49 | 1.79 |
| std-FTSEMIB | 1.28 | 2.66 | 1.71 | 1.01 | 1.58 | 0.86 | 1.25 | 0.99 | 1.32 | 1.33 | 1.60 |
| std-MDAX | 3.66 | 6.14 | 3.85 | 3.38 | 4.24 | 2.93 | 3.80 | 3.44 | 5.15 | 4.41 | 5.58 |
| rij-FTSE100 | 0.21 | 0.62 | 0.66 | 0.41 | 0.24 | 0.43 | 0.32 | 0.19 | 0.33 | 0.15 | 0.12 |
| rij-CAC40 | 0.30 | 0.73 | 0.80 | 0.31 | 0.61 | 0.36 | 0.55 | 0.22 | 0.50 | 0.29 | 0.42 |
| rij-DAX | 0.30 | 0.75 | 0.76 | 0.37 | 0.58 | 0.46 | 0.48 | 0.23 | 0.43 | 0.17 | 0.34 |
| rij-MDAX | 0.25 | 0.64 | 0.75 | 0.62 | 0.42 | 0.26 | 0.36 | 0.16 | 0.35 | 0.20 | 0.31 |
| rij-IBEX35 | 0.10 | 0.70 | 0.68 | 0.37 | 0.47 | 0.43 | 0.51 | 0.25 | 0.29 | 0.22 | 0.34 |
| rij-FTSEMIB | 0.22 | 0.78 | 0.78 | 0.23 | 0.67 | 0.36 | 0.56 | 0.25 | 0.54 | 0.15 | 0.31 |
| comb-FTSE100 | 3,741 | 4,005 | 4,095 | 4,095 | 4,095 | 4,186 | 4,371 | 4,656 | 4,753 | 4,851 | 4,950 |
| comb-CAC40 | 666 | 703 | 703 | 703 | 703 | 703 | 703 | 703 | 703 | 741 | 780 |
| comb-DAX | 406 | 406 | 406 | 406 | 406 | 406 | 406 | 435 | 435 | 435 | 435 |
| comb-MDAX | 435 | 496 | 496 | 496 | 561 | 595 | 666 | 780 | 861 | 990 | 1081 |
| comb-IBEX35 | 276 | 300 | 300 | 300 | 325 | 406 | 406 | 406 | 435 | 496 | 496 |
| comb-FTSEMIB | 351 | 406 | 406 | 465 | 465 | 496 | 496 | 561 | 630 | 666 | 741 |
List of sample countries’ stock index, the currency used, and the period covered
| Country | Index | Portfolio designation | No. of companies | Currency | Period |
|---|---|---|---|---|---|
| Germany | DAX – Equity Index | Portfolio A | 30 | Euro | 2008–2018 |
| MDAX – Equity Index | Portfolio F | 60 | Euro | 2008–2018 | |
| England | FTSE 100 – Equity Index | Portfolio B | 100 | Euro | 2008–2018 |
| France | CAC 40 – Equity Index | Portfolio C | 40 | Euro | 2008–2018 |
| Italy | FTSE MIB – Equity Index | Portfolio E | 40 | Euro | 2008–2018 |
| Spain | IBEX 35 – Equity Index | Portfolio G | 35 | Euro | 2008–2018 |