Saturday, November 16, 2013

Vanguard Introduces Its Modification of the 4% Withdrawal Rule

Readers of this blog will note that I devote a fair amount of energy ranting against the 4% Withdrawal Rule (and other "Safe" withdrawal rates) as retirement decumulation strategies.  In addition, I'm generally not all that impressed with proposed modifications to the 4% Rule designed to somehow make it more workable.  Vanguard recently announced its proposed modifications in a paper entitled, "A More Dynamic Approach toSpending for Investors in Retirement."  They suggest a two-step process for determining an annual spendable amount payable from accumulated savings:  Step 1:  Take X% of end-of-the-previous-year accumulated savings.  Step 2:  Subject the result of Step 1 to a corridor, the ceiling of which is (1+Y%) of the spendable amount from the previous year and the floor of which is (1-Z%) of the spendable amount from the previous year, where "X" depends on the "planning horizon" and investment philosophy and "Y" and "Z" are arbitrarily chosen upper and lower limits (they suggest a value of 5 for Y and 2.5 for Z).  Readers of the paper who get as far as Appendix 3 will note that the example set forth in this appendix describes a slightly different approach than the approach described in the body of the paper, which I am assuming is an error).

While the Vanguard modification of the 4% Rule does make the approach more dynamic (i.e., it reflects actual investment experience to some degree), I believe this approach to be inferior to the actuarial approach suggested in this website for the following reasons:

As is the case for most "safe" withdrawal rate strategies, it defines success as not outliving accumulated assets.  It does not adequately address the risk of under spending.

It doesn't attempt to provide constant real dollar spendable income in retirement.

It doesn't coordinate with other forms of retirement income such as immediate or deferred annuities and it doesn't reflect bequest motives. 

With all the adjustments required for different planning horizons and investment philosophies, it is not appreciably simpler than the actuarial approach set forth in this website (particularly if you use the assumptions and algorithm I recommended several posts ago).