One commenter the other day had a good suggestion: Publish the Excel spreadsheet that we use in our safe withdrawal rate research. Great idea! There is only one problem: we didn’t use Excel to calculate any of the SWRs. We did use Excel to create some tables, but the computation and most charts were all done using GNU Octave, a free number-crunching programming language, similar to Matlab.
But we still liked the idea of creating a tool to run some quick SWR calculations. In Octave, we can calculate a large number of simulations and calculate safe withdrawal rates over a wide range of parameter value assumptions. Millions and millions of SWRs over many different combinations of parameter values (retirement horizons, final asset value target, equity shares, other withdrawal assumptions). That would have been cumbersome, probably even impossible to implement in Excel. But a quick snapshot on how one single set of SWR parameters would have performed over time? That’s actually quite easy to do, even though there are 1,700+ different retirement cohorts between 1871 and 2015.
Update 2/10/2016: I added the gold and cash returns.
Gold returns are only completely trustworthy after 1968 when I got the London Fixing time series via Quandl. Before that, I had to rely on annual data from OnlyGold.com. If someone has a better (monthly) time series for 1871-1967 please let me know!
For cash returns I use:
3-month T-bill interest rates from the Federal Reserve starting in 1934. Monthly data.
I have annual data for going back to 1928 from NYU-Stern. Data gathered via Quandl.
For 1871-1927 I use annual data on 1-year T-bill yields from Prof. Rober Shiller. It’s not exactly ideal to splice it this way but it’s the best I can right now. If someone has better data, please let me know!
If you’ve been following our series on withdrawal rates (part 1 here) you have noticed that we’re quite skeptical about the 4% rule. That would be especially true for early retirees with a much longer horizon than the standard 30 years. Though, by reading through some of the research from the heavy hitters in the retirement research world, even the foundation of the 4% rule over 30 years seems to be crumbling a little bit:
Wade Pfau has been warning that due to high equity valuation and low bond yields the Trinity Study success rates are likely overrated. His argument is similar to ours in Part 3 of this series: we live in a low return world now and comparisons with past average returns could overstate the success probability of the 4% rule. He uses a slightly different methodology (Monte Carlo simulations) but reaches similar results.
Even Michael Kitces, arguably one of the great defenders of the 4% rule, has (inadvertently?) demonstrated that the 4% rule over 30 years isn’t all that sound. In the discussion after the famous “ratcheting post,” some readers (including yours truly) pointed out that we can’t replicate the success of the 4% rule with 1965/66 starting dates. Nothing to worry about, Kitces replied, all you needed to do is to use a very short-term bond (1-year T-bills) for the bond allocation, and you sail smoothly during the 1970s. Who would put 40% of the portfolio into 1-year Treasury bills (essentially CD interest rate) rather than trying to harvest the term premium of longer-term bonds? Very easy: someone with 20/20 perfect hindsight who knew that longer duration 10Y bonds will get hammered in the 70s and sink the 4% rule even over a 30-year horizon.
And I just became a little bit more skeptical about the 4% rule even over a 30-year horizon! But there is (at least) one prominent 4% SWR firewall still standing. In countless blog posts, discussions, forums etc. I have heard this quote (or variations of it):
“The 4% rule worked just fine during the Tech Bubble and Global Financial Crisis”
Welcome back to the Safe Withdrawal Rate Series. Last week we wrote about how Social Security can impact the SWR estimates. Even under the most optimistic assumption (no changes to the Social Security benefits formula), we didn’t think that the 4% withdrawal rate is safe.
But how about tinkering with the inflation adjustments, also called Cost-of-Living adjustments (COLA)? I often hear that one way to save the 4% rule in periods when the stock market doesn’t cooperate is to not do inflation adjustments for a few years. Or simply utilize the fact that we all potentially spend less (in real terms) as we age! How much can we push the initial withdrawal rate in that case?
J. Money, the personal finance blogger who runs Budgets are Sexy and RockstarFinance asked yours truly to write a guest post! Wow, what an honor! And, it turns out, this is actually my first guest post ever (not counting the “Christopher Guest Post” on the Physician on FIRE blog two months ago because that’s actually an interview). What did I write about? Initially, I proposed to go on an all-expenses-paid trip to Tahiti to review some luxury resorts and report back, uhm, some time later this year. But J$ had another brilliant idea: write about my favorite finance pet peeves. And it got published today:
After a one-week hiatus over the holidays when we wrote about a lighter topic (dealing with debt, booze, and cigarettes, go figure), let’s return to the safe withdrawal rate topic. We’ve already looked at:
the sustainable withdrawal rates over 30 vs. 60-year windows (part 1),
and the current expensive equity valuations (part 3).
The bad news was that after all that number-crunching, the sensible safe withdrawal rate with an acceptable success rate melted down all the way to 3.25%. So much for the 4% safe withdrawal rate! That 25x annual spending target for retirement savings just went up to 1/0.0325=30.77 times. Ouch! Sorry for being a Grinch right around Christmas time!
But not all is lost! Social Security to the rescue! We could afford lower withdrawals later in retirement and, in turn, scale up the initial withdrawals a bit, see chart below. How much? We have to get the simulation engine out again!