InvestingSimulation

clc; clear all;
%% Init params
opt = {'il','us','lin'};

annualYield.il = 4 / 100; % [pct]
annualYield.us = 4 / 100; % [pct]
annualYield.lin = 0; % [pct]
annualInflation.il = 0; % [pct]
annualInflation.us = 0; % [pct]
annualInflation.lin = 1.5 / 100; % [pct]
tax.il = 25 / 100; % [pct]
tax.us = 25 / 100; % [pct]
tax.lin = 0; % [pct]
dividendTax.il = 0; % [pct]
dividendTax.us = 25 / 100; % [pct]
dividendTax.lin = 0; % [pct]
annualDividend.il = 2 / 100; % [pct]
annualDividend.us = 2 / 100; % [pct]
annualDividend.lin = 0; % [pct]
annualfundExpense.us = 0.1 / 100; % [pct]
annualfundExpense.il = 0.4 / 100; % [pct]
annualfundExpense.lin = 0; % [pct]
for iOpt=1:numel(opt)
    monthlyYield.(opt{iOpt}) = (1+annualYield.(opt{iOpt}))^(1/12)-1;% [pct]
    monthlyInflation.(opt{iOpt}) = (1+annualInflation.(opt{iOpt}))^(1/12)-1;% [pct];
    monthlyFundExpense.(opt{iOpt}) = (1+annualfundExpense.(opt{iOpt}))^(1/12)-1; % [pct]
end
actionType.il = 'pctg';
actionType.us = 'fixed';
actionType.lin = 'fixed';
actionCost.il = 0.07 / 100; %[pct]
actionCost.us = 28; % [nis]
actionCost.lin = 0; % [nis]
initialCapital = 1e5; % [nis]
monthlyDeposit = 1e4; % [nis]
currencyChangeCost.us = 0.5 / 100; % [nis]
currencyChangeCost.il = 0; % [nis]
currencyChangeCost.lin = 0; % [nis]
years = 20;
monthsPerDeposit = 1;
line.il = 'b+';
line.us = 'r+';
line.lin = 'g+';

%% Simulate investment
optOn = 1:3;
capital = zeros(years*12, numel(optOn));
gain = zeros(years*12+1, numel(optOn));

for iOpt = optOn
    % Initial buyout
    capital(1,iOpt) = initialCapital;
    capital(1,iOpt) = capital(1,iOpt) * ( 1-currencyChangeCost.(opt{iOpt}) ); % currency change
    switch actionType.(opt{iOpt}) % Initial action cost
        case 'pctg'
            capital(1,iOpt) = capital(1,iOpt) * ( 1-actionCost.(opt{iOpt}) );
        case 'fixed'
            capital(1,iOpt) = capital(1,iOpt) - actionCost.(opt{iOpt});
    end

    % Continuous progress
    for iMonth = 2:(years*12-1)
        % Gain yield - continuously
        gain(iMonth-1,iOpt) = capital(iMonth-1,iOpt) * ( monthlyYield.(opt{iOpt}) - ...
            monthlyFundExpense.(opt{iOpt}) - monthlyInflation.(opt{iOpt}) );
        capital(iMonth,iOpt) = capital(iMonth-1,iOpt) + gain(iMonth-1,iOpt);

        % Gain dividends every 12 months
        if mod(iMonth, 12) == 0 % Every end of year
            dividend = capital(iMonth,iOpt) * annualDividend.(opt{iOpt}); % get dividend
            capital(iMonth,iOpt) = capital(iMonth,iOpt) - dividend; % reinvest dividend
            taxedDividend = dividend * ( 1-dividendTax.(opt{iOpt}) ); % tax dividend
            capital(iMonth,iOpt) = capital(iMonth,iOpt) + taxedDividend; % reinvest dividend
        end

        % Timely deposit
        if mod( iMonth, monthsPerDeposit ) == 0 % deposit every monthsPerDeposit
            deposit = monthlyDeposit * monthsPerDeposit;
            deposit = deposit * ( 1-currencyChangeCost.(opt{iOpt}) ); % currency change
            switch actionType.(opt{iOpt}) % action cost
                case 'pctg'
                    deposit = deposit * ( 1-actionCost.(opt{iOpt}) );
                case 'fixed'
                    deposit = deposit - actionCost.(opt{iOpt});
            end
            capital(iMonth,iOpt) = capital(iMonth,iOpt) + deposit;
        end
    end

    % Final buyout (tax event)
    totalGain = sum(gain(:,iOpt));
    capital(iMonth+1,iOpt) = capital(iMonth,iOpt) - totalGain * tax.(opt{iOpt});
end

% Plot results
fig = figure(); hold on;
xlabel('Months'); ylabel('Capital');
msg = sprintf('%d%% annual yield, %d%% annual dividend, commisions like in IBI.', ...
    4, 2);
title(msg);
for iOpt = optOn
    plot(1:size(capital,1), capital(:,iOpt), line.(opt{iOpt}))
end
legend(opt, 'Location','northwest');