In my way too premature thoughts about portfolio consumption strategies cash management plays an important part. I will try to give a short summary of my thoughts which are related to the topic.
As an introduction, the more I think about it, the more I am convinced that the key to portfolio consumption should be not the withdrawn amount, but the number of units of (for model calculations) one global stocks fund sold. This should prevent underconsumption and make sure that our money is mostly spent on us. While I love our children, I don’t think that leaving them 3 times more money than we had at the beginning of the portfolio consumption will do any good to anyone. So, withdrawal strategies I consider are set up to consume a significant part of the portfolio while we are alive. I deliberately take the risk of fluctuations in the amount of funds available for the chance of increasing them with the portfolio growth.
My first naive proposition to sell the same number of units of accumulating global stocks fund was met with a very reasonable argument: when you start, the value of a unit is much lower than in 10-20 years with distributions accumulated. So let’s say you count for 50 years of portfolio consumption (well, I do), you liquidate every year 2% of the original amount of fund units in the portfolio. Even in a perfect model market, where one fund unit grows by 5% each year, the value of one unit grows by 50% in 9 years and doubles in 15 years. So, with this methods, at the beginning you massively underconsume, just at the time when you rather want, and capable, to profit from your wealth, and later your portfolio grows faster than you can spend.
So it clearly needs some gliding path to account for the fact that while you want to, calculation-wise, spend your entire portfolio in 50 years, the value of fund units is different at different times. You can of course model it as a geometric sequence: the value of unit increases by 5% each year, so you just need to sell 5% less units each consequent year. But for long sequences you end with a simple and trivial result: if you expect 5% appreciation every year, you should sell 5% of the current value of the portfolio every year. In a perfect situation, the value of your portfolio stays constant - you don’t consume it, but “merely keep it for the next generation”. But I want to actually consume it!
One “natural” mechanism of creating such a gliding path that I came up with is to use distributing funds of global stocks and every year collect dividends from all (remaining) fund units as well as sell some, a fixed amount of units, e.g., corresponding to 2% of the starting portfolio size. This way, a part of the income generated by fund units still held is not reinvested, but consumed way before they are sold. With time, the number of units generating dividends is decreasing, but the value of each unit is still increasing, although not as fast as with dividends reinvested. At some point, the value of units sold each year becomes greater than the initial value of sold units plus collected dividends.
Some simulations are in progress.
Now about the use of cash in such withdrawal strategies:
- Cash supplement.
In this strategy, a certain fraction of initial portfolio is reserved as cash. It is regularly and uniformly added to the “income” from stocks generated as described above. After it’s gone the rest of income is provided by stocks only.
For example, you reserve 10% of initial portfolio value as cash. The rest is invested in a distributing global stocks fund, and you know how many fund units correspond to 1% of the initial portfolio value (i.e., total number of fund units/90). The first month is January, but the cash flow from the portfolio starts only in March.
- A dividends distribution cycle finishes in March. In the end of March, you sell the number of units corresponding to 0.5% of the initial portfolio value.
- The dividends, selling proceeds and the amount of cash corresponding to 0.25% of initial portfolio value is transferred to the checking account for spending.
- Repeat every quarter.
This setup would correspond to initial annualized withdrawal rate of 3% + dividend yield, around 4.8%.
After 10 years cash is gone, and the rest of income is provided by stocks only.
All in all, the strategy is set to run for 45 years (i.e., last holdings of stocks will be sold 45 years after start).
This approach would somewhat correspond to “bond” or “cash tent” in withdrawal strategies popular in USA, although they do it somewhat differently, I think.
The same approach can be used with other diversifiers, such as gold or broad commodity fund. You reserve a certain portfolio fraction, sell every year a preset amount of units, no matter the price, and add it to your income stream. The main characteristics of a “diversifier” is that it is consumed relatively fast, and the long term growth is generated by stocks.
Advantages: easy to implement. The fraction of cash in the portfolio is decreasing with time, which improves long term yield.
Disadvantages: inflexibility. Once the cash is consumed, available funds fluctuate almost like the stocks market, although the dividend component should add some stability. While I expect such fluctuations, I also want to be somewhat in control.
- Cash buffer.
You choose a certain term, for which you keep money to spend in cash. I am thinking about 3 or 5 years. Then you start with a certain fraction of your initial portfolio in cash. The cash from the buffer is withdrawn every month and refilled by dividends and selling proceeds from the stocks part. The amount spent is adjusted regularly, e.g., once per quarter or year. The timing just needs to include both spending and refilling steps.
Let’s say you go for 3 years (36 months) buffer and the initial cash value of 15% of the initial portfolio value. The rest is invested in a distributing global stocks fund, and you know how many fund units correspond to 1% of the initial portfolio value (i.e., total number of fund units/85). The first month is January.
- On January, February and March you withdraw from the cash buffer an amount equal to (its initial value)/36.
- A dividends distribution cycle finishes in March. In the end of March, you sell the number of units corresponding to 0.5% of the initial portfolio value.
- The dividends and selling proceeds are added to the cash buffer.
- The monthly withdrawal amount is readjusted to (current value of the cash buffer)/36.
- Repeat every quarter.
This setup would correspond to the initial withdrawal rate of 5% p.a. and is set to run for 45.5 years.
Advantages: still quite easy to implement. Available funds are changing with the evolution of the portfolio value, but these fluctuations are dampened by the buffer. On the other hand, you automatically get more money to spend when the portfolio is doing well - remember, my goal is to prevent underconsumption!
Disadvantages: high and permanent cash component. You don’t spend cash with time, it is always in the portfolio. You also need to manage it with respect to depositor guarantee and so on.
High allocation to cash decreases long-term yield - but you can also stop playing if you have won.
- Cash reserve.
A certain, rather high fraction of initial portfolio is reserved as cash. You define how much you want to withdraw from the portfolio, and if the “income” from stocks generated as described above is not sufficient (it won’t be for many years), you add the missing amount from the cash reserve. At some point, the income from stocks alone reaches the desired level of withdrawals, so you don’t need the reserve anymore.
While the idea sounds simple, it is difficult to calculate how much of cash reserve to start with. I am playing around with it, but even with the perfect model market, there is a complex interaction of multiple parameters: target withdrawal (as the percentage of initial portfolio value), dividend yield and CAGR. It can “fail”, meaning you run out of cash reserves and can’t maintain the desired withdrawal amount while the income from stocks have not reached this level yet - but you don’t spend all your portfolio too early, like in fixed withdrawal amount strategies.
Advantages: well, theoretically is should be very flexible and with decreasing cash component, that improves long-term yield. But this is only if you get through first 20 years or so.
Disadvantages: complexity even in model calculations and unpredictability of real development.
Not sure when I can do something serious about the last one. But hey, I am glad to share some ideas and personally I have time to figure things out.