O artigo faz a ligação com William Bernstein’s plan that he outlined for Business Insider , que diz:
Put equal amounts of that 15% into just three different mutual funds:
• A U.S. total stock market index fund
• An international total stock market index fund
• A U.S. total bond market index fund
Over time, the three funds will grow at different rates, so once per year
you'll adjust their amounts so that they're again equal.
That's it.
Modelando esta estratégia de investimento*
Escolhendo três fundos do Google e executando alguns números.
MUTF: VTSMX Vanguard Total Stock Market Index
MUTF: VGTSX Vanguard Total International Stock Index Fund Investor Shares
MUTF: VBMFX Vanguard Total Bond Market Index Fund Investor Shares
O índice internacional de acções remonta apenas a 29 de Abril de 1996, pelo que foi modelada uma série de 21 anos. Com base em 15% de um salário de $550 por mês, com vários aumentos anuais:
annual salary total contributions final investment
rise (%) over 21 years value after 21 years
0 20,790 43,111
1 23,007 46,734
2 25,526 50,791
Em termos gerais, este investimento duplica o valor das contribuições ao longo de duas décadas.
Nota: As taxas de reequilíbrio não estão incluídas na simulação.
Abaixo está o código utilizado para executar a simulação. Se tiver Mathematica pode tentar com fundos diferentes.
funds = {"VTSMX", "VGTSX", "VBMFX"};
(* Plotting the fund indices *)
{tsm, ism, tbm} = FinancialData[#, {"April 29, 1996",
DateList[], "Month"}] & /@ funds; DateListPlot[
Transpose[{First /@ #, 100 Last /@ #/#[[1, 2]]}] & /@
{tsm, ism, tbm}, PlotLegends -> funds, PlotLabel ->
"Indices from month-end April 1996 rebased to 100"]
(* Plotting the investment contributions *)
salary = 550;
investment = salary*0.15;
inflation = 2;
nmonths = Length[tsm] - 1;
ny = Quotient[nmonths, 12];
iy = Array[investment/3 (1 + inflation/100)^(# - 1) &, ny];
d = Take[Flatten[ConstantArray[#, 12] & /@ iy], 12 ny];
DateListPlot[Transpose[{Take[First /@ tsm, 12 ny], 3 d}],
PlotLabel -> Row[{"Monthly contributions with ",
inflation, "% inflation - Total = ",
Total[3 d]}], PlotRange -> {Automatic, {0, Automatic}},
PlotMarkers -> {Automatic, 6}, FrameLabel -> {"Time",
Rotate[Style["$", 12], Pi/2]}, ImageSize -> 380]
(* Calculating & plotting the investment values *)
{tsm2, ism2, tbm2} = Take[Ratios@# - 1, 12 ny] & /@
Map[Last, {tsm, ism, tbm}, {2}];
d2 = 0;
ds = {};
eachyear[yr_] := Last /@ Function[series,
AppendTo[ds, Total@Array[(d[[# + 12 (yr - 1)]] +
If[# == 1, d2/3, 0]) Apply[Times,
1 + series[[# + 12 (yr - 1) ;; 12 yr]]] &,
12]]] /@ {tsm2, ism2, tbm2}
vals = Array[(d2 = Total@eachyear[#]) &, ny];
rd = Last /@ Partition[Take[First /@ tsm, {2, 12 ny + 1}], 12];
DateListPlot[Transpose[MapThread[
{{#1, #2[[1]]}, {#1, #2[[2]]}, {#1, #2[[3]]}} &,
{rd, Partition[ds, 3]}]],
PlotMarkers -> {Automatic, 8}, PlotLabel -> Row[{
"Individual fund investment values over ", ny,
" years"}], PlotLegends -> funds, Epilog -> {Red,
Arrowheads[0.06], Arrow[{{{2007, 10, 1}, 12000},
{{2008, 10, 1}, 9000}}]}, FrameLabel -> {"Time",
Rotate[Style["$", 12], Pi/2]}, ImageSize -> 400]
Note acima como o índice de obrigações (VBMFX) preserva o valor durante o crash de 2008. Isto ilustra a lógica de diversificação entre diferentes tipos de fundos.
DateListPlot[Transpose[{rd, vals}],
PlotMarkers -> {Automatic, 8}, PlotLabel -> Row[{
"Total investment value over time - Final value = ",
Last[vals]}], FrameLabel -> {"Time",
Rotate[Style["$", 12], Pi/2]}, ImageSize -> 400]