Future returns and their impact on SWRs

October 16, 2014

Today I wanted to talk about the forecasting of future returns and more importantly what implications future returns have for SWRs (Safe Withdrawal Rates). As I showed in my last post, the first 10 year period real return in retirement is the best predictor of SWRs for 30 year retirement periods. Thus by creating a model for returns for the next 10 years based on where assets are priced today we can get a better idea as to the applicability of the traditional 4% SWR for future retirees.

There’s a been lot of discussion over the last couple of years in the financial blogosphere about future equity returns. Most of the that discussion is centered around US equity markets being over valued and therefore leading to very poor returns going forward, for anywhere from the next 5 years to the next 20 years. The analysis goes something like this; you take historical valuation figures based on different parameters such as Shiller PE, MarketCap to GDP, Q ratio and see what the historical forward returns where for different levels of starting valuation. Then you compare that history to today’s valuation level and make a statistical forecast for future returns. It’s more complicated than it sounds but that is essence of what the process is to arrive at return forecasts. The best summary of these types of analyses I’ve found anywhere is this post from GestaltU. There is a lot of gory detail (or awesome detail for folks like me) in the post and associated caveats but here is the punch line that we need to consider.

Butler forecasted returns oct 2014

Not so pretty right? The most probable compounded US equity returns for the next 10 years is about -1%. This could imply a rethinking of the 4% SWR. This being a statistical analysis there is a potential range of outcomes. I wanted to get a feel for what those range of outcomes were in the past with specific years attached to it – after all, this is based on historical data anyway. Sometimes the human brain needs context and a story behind the data to derive a better understanding. I went to my handy dandy data base of historical stock returns that I use for my SWR analyses and added the Shiller PE (CAPE) data to it, as well as bond returns, 60/40 portfolio returns and inflation. At the end of the day we care about total portfolio returns, not just equity returns. I then sorted all 10 year period returns starting in 1929 by CAPE range. Below is the summary. Highlighted is the CAPE range of the US equity market today, greater than 25.

Ten year historical returns by CAPE range oct 2014

The data in the table pretty much agrees with the GestaltU data. Forward stock returns from high valuation markets are low. Stock returns pretty much go up with decreasing starting valuation as expected. A couple of interesting things to note in the table are that bonds returns are highest at both high starting equity valuations and low starting equity valuations. Also, inflation increases as starting equity valuation decreases. This is not the place to delve into the reasons why but the important point is that these effects are all important to and affect what we care about which is total real portfolio return. The portfolio returns also decrease directly with increasing equity valuation but note that the absolute numbers are not as bad. A 2.85% avg portfolio real return from the highest valuation tier is a lot better than a -1% stock only return that starts freaking investors out. Now recall that the first 10 yr period return for the worst case retiree in history, which defined the 4% SWR rule, was -1.26% real per year for a 60/40 portfolio. So, this simple look into the details tells me that the 4% SWR rule is probably still OK. But could some of the future periods be worse than any other period in history? Yes. I think for more insight here we need to look into even more detail at the historical data. Below I break out all the 10 year periods with CAPE ratios greater than 20. The table is sorted by CAPE ratio from highest (most expensive) to lowest (cheapest).

Detailed Ten year historical returns by CAPE oct 2014

Along with CAPE I also added the yield of the 10 year note at the start of the period. For example, in the begging of 2000 the CAPE ratio was over 42 and the 10 yr yield was 5.11%. Note that indeed the 10 year period starting 1966 started from a high valuation, although not in the top tier, and produces almost the lowest total portfolio return with both negative real stock returns and bond returns! Now, could it be worse than 1966 in the future thereby forcing a lowering of the 4% SWR? To look at that I highlighted all the past years in yellow that could be called similar to today, with high equity valuations and low bond yields. Looking at the data and thinking about the story behind those periods makes me think that 1937 could be a similar parallel for today. Beginning of 1937 was about 8 years after the Great Depression. Today we stand at close to 7 years after the Great Recession. Maybe? Who knows but worth a think. The data is the data though – high equity valuations and low bond yields is what we face.

You could even say that there is no precedent for where we are today with CAPE ratios of over 25 and bond yields below 2.5%. And that could imply that the 4% rule may fail going forward. Definitely a possibility. But I think the important point is that it would take more than weak first 10 year equity returns to kill the 4% SWR. It would take a similar but even worse brew than the 1966 period which combined high starting equity valuations, with rising bond yields, and rapidly rising inflation.

If that was where we ended it would indeed be a worrying picture. And then maybe the best recommendation would be to reset expectations to a lower SWR. But the problem with the all the above is that we have taken a very narrow view of the brave new investing world we live in. The entire discussion above and in most of the blogosphere is solely focused on US equity markets. There are other markets out there with better valuations. Most of the discussion around the potential failure of the 4% SWR assumes a US large cap stock and US intermediate government bond only allocation. There are better asset allocation methods out there. There are portfolio strategies that seek to enhance return and minimize risk which also help maintain SWRs. There are better retirement withdrawal and spending models that help combat poor early returns in retirement. Before we go off concluding that a 4% SWR won’t cut it anymore we need to look at all of these and what impact they have on SWR. I’ve done that in many previous posts but I plan to recap and summarize most of that work in future posts.

In summary, future US equity returns are probably going to be lower than in the past due to today’s high valuations. But that is only part of the story when it comes to determining SWRs. Despite these headwinds I think that with the combination of better asset allocations, better portfolio strategies, and better spending and withdrawal models the 4% SWR can continue to serve retirees well into the future.

When you retire matters a lot more than you think

October 13, 2014

The starting year of retirement makes a huge difference in the success or failure of a retirement plan. This is the key difference between the accumulation phase of investing and the withdrawal phase of investing. Yet the majority of investing writing does not take this key difference into account when speaking of returns, asset allocation, planning, etc. So, lets look at how important the starting year of retirement is to a successful outcome and what potential a retiree can do to mitigate this risk.

Why does the starting year of retirement matter in the first place? It is because retirement involves yearly withdrawals from the portfolio. Once you start making yearly withdrawals from a portfolio the sequence of investment returns, the year by year order of those returns influences how much you can withdraw from that portfolio and have it last for the full retirement period. This is NOT the case pre-retirement where there are no yearly portfolio withdrawals. The figure below (from Gestaltu) shows three separate return paths to the same final total portfolio value.

Alternate return parths chart oct 2014

The blue line shows a constant return path. The red line shows an early bull market followed by a weak market and the green line shows an early bear market followed by a strong bull market. For an investor in wealth accumulation mode, all three return paths have the same result – the same end wealth. But that’s not the case for retirees. The blue line retiree enjoys a consistent retirement and in fact their safe withdrawal rate (SWR) can be set equal to the portfolio return. Unfortunately, the blue line return assumption does not exist. It never has. Annual returns are lumpy. There are some good years and some bad years. And it turns out the order of good vs bad years makes all the difference for retirees. In retirement literature this is called sequence of returns risk or path dependence in retirement. The red line retiree in the figure above can enjoy much higher withdrawals from their retirement portfolio than the green line retiree even though the returns over the entire period are exactly the same. Using the blue line return as the SWR, the blue line retiree would have a successful retirement. The red line retiree would have a wildly successful retirement and the green line retiree would run out of money. For a great case study of this particular scenario see here.

If the sequence of returns matter in retirement then how can we measure it’s impact? We can look at the correlation between time period returns and SWRs. As hinted at in the previous paragraph early returns are much more important than later returns. The chart below show this quite clearly. From Michael Kitces who has a great recent post on this topic.

SWR correlation by return time horizon oct 2014

Turns out that 10 year real returns have the highest correlation with SWRs. Also, notice that nominal returns don’t matter nearly as much as do real returns which makes sense since retirement is about keeping inflation adjusted spending consistent. 10 year real returns explain almost 85% of the SWR. This is where the attention should be focused – on the first 10 years of retirement. Now lets look at some specific retirees of the past to give you a feel for the impact of these numbers. See the table below.

Rolling 10 and 30yr 60 40 portfolio return history summary oct 2014

In the table I show the 60% stock/40% bond portfolio 10 year and 30 year period return figures for various years of starting retirement. The first two rows show the worst case retirement periods in history, the 30 year periods starting in 1966 and 1929. The 1966 period alone solely determines the historical SWR. See here for more on 1966. As the table shows, the 30 year period returns are pretty darn good even for the 1966 retiree. However, what really hurt the 1966 retiree was the first 10 years of retirement where their returns were negative on a real basis. The 1929 retiree despite the worst stock market decline in history experienced higher real returns than the 1966 retiree (even though nominal returns were lower). As they say, you can only eat inflation adjusted income. Just for kicks, now look at Mr and Mrs 1982. Wow! What a retirement. Simply, really, by luck of the draw of when they retired.

What does the future hold? For the 1999 retiree, the first 10 years have definitely not been great but they have not been as bad as the past. In fact it looks like the 1999 or the 2000 retiree are proceeding to a successful retirement (see here for the latest data). But it was dicey those first 10 years. And what about those who are considering retiring shortly? That is a whole other topic for a post but what needs to be considered is clear. Retirees need to consider what weak returns during the first 10 years of retirement can do to their portfolios and put plans in place accordingly. I’ve touched on this topic in other posts on various portfolio options and spending strategies that can improve the probability of a successful retirement. I’ll return to it again in future posts. There is much to say.


Recipe for a happy retirement (2014 edition)

October 7, 2014
Impromptu intimate concert at our RV site

One of our many serendipitous social encounters; an impromptu concert at our RV site this week!

Hard to believe it has been 2 years since I last updated my recipe for a happy retirement. And 2 years before that I had the original post. Every 2 years seems like a nice interval to revisit my thoughts in this area. We are now getting close to completing 5 years on the road living in our RV and 9 years since we left the daily 9-5 grind and started on this great new life adventure. It’s been an amazing adventure that continues to improve. I can’t recommend it enough.

I’ll also add that in the past 2 years we have met many couples and individuals that are making the same lifestyle choices Nina and I have made without being ‘retired’. That word has less and less meaning these days for many including us. These people work on the road and have found ways to have mobile or seasonal sources of income and to keep their costs of living low. I truly admire these folk and having listened to many of their stories I often think we should have done this sooner. OK, but this post is about my thoughts on retirement so let’s get to it.

Below I reproduced the original recipe for a happy retirement post, along with my comments from 2012 and have then added my most recent observations for 2014.

I’ve come up with four areas that I think every retiree needs to think about and have a plan for;

1. Financial – this one is the most obvious. You can’t retire unless you have the financial means to do so. It may just be social security, or a pension. It could be 100% savings. What I think is important is to have a plan that you can mark your progress against. And more importantly a plan that is flexible, that takes account some big what-ifs. This is one major reason I think retirees get ‘scared’ back into the workforce and in the worst case have no choice but going back to work. This is one of the major reasons I started this blog – to help people with this part of their retirement.

[2012]I now recommend that that ‘plan’ I mentioned should be the IVY timing portfolio or timing the Permanent Portfolio for the majority of retirees (see my latest post on the subject here). The standard retirement models, e.g. 60/40 stocks bonds, are not the best solution in particular during retirement when you’re in withdrawal mode, not wealth building mode, and capital preservation is key. For those so inclined I think its possible to do even better with a dividend/income approach I outline here, although right now I outright trade equities versus options.

[2014] This has been the biggest change since 2012.  I have personally gone almost exclusively to quantitative investing methods (I still do some active bond management). That includes the different versions of the IVY portfolios. My latest update on all the portfolios I track is here. I personally now use the GTAA aggressive portfolios. I also use several of the quantitative stock portfolios I’ve discussed in the last year on the blog. I do no manual stock picking or trading anymore. What I have found is that even if you are one of the less than 5% of individuals who has the behavioral capacity to be a very active investor it is simply not worth the investment in time and emotional ups and downs. The bang for the buck is simply not there. I’d rather be doing something else. The majority of investors can’t even stick with simple buy and hold strategies.

As far as progress to a successful retirement, things have gone pretty well over the last 9 years since I first started withdrawing from my retirement portfolio. I will do a detailed analysis at the end of next year for the 10 year mark but so far my CWR is below my SWR when I started and the total portfolio value is higher as well. The RV life has been a big contributor to this outcome as it allows us to be very flexible in retirement spending and keep our costs down as well.

2. Social – work provides a lot of the social interactions we have in our lives. Many people’s friends are made through the workplace. When you retire you lose this unless you retire at the same time as your friends and in the same area. If you retire early most of your friends are still working. Without these social connections you can easily get bored, lonely, etc… Faced with a loss of these social connections you need to actively work at this in retirement. Do you join a social club? a golf club? volunteer for certain organizations? How are you going to fulfill this part of your life? This was a huge loss for my grandfather who was the social center of his small immigrant community. He has not been the same since. In our full-time RV lifestyle this has been our biggest challenge. We’re still working on it.

[2012] Well, all I can say is challenge conquered! Full-time RV’ing has turned out to be maybe the most social thing we have ever done. Our social life is a lot more full than it ever was while we were both working. And because of this new found socialness we are enjoying our lives even more. Many of our new connections have come from Nina’s RV blog, our volunteer experiences, serendipitous meetings at campgrounds, and even social media. So, I would even put more emphasis on the importance of having social connections in retirement. Not too long ago Nina posted about this unexpected surprise for us.

[2014] And the party continues! We’re even more social now than 2 years ago. We have formed some amazing friendships on the road and continue to do so. These relationships and interactions vary from brief visits and happy hours over campfires to week long rendezvous or caravans to spend quality time together. Now we even have to be careful not to have too much socializing. I still need to give my introverted side some alone time every once in a while.

3. Mental – work usually provides much of the mental/intellectual stimulation we get in our daily lives. What do you do when this goes away? Do you have a hobby to keep your mind active? Just relaxing, watching TV or surfing the internet is probably not going to be enough. Even if your work was very physical, and not mental, what do you do as you age and your ability to engage in physical activities goes away? Often this can be combined with #2. There are many ways to fulfill this need like volunteering and in today’s tech world many remote possibilities enabled by the internet. For me, my interest in investing fulfills this role. And I try to parlay this intellectual interest into helping me with my social and financial areas. On-line forums, blogs, social networks all help in this regard. I have seen many retirees struggle in this area. They find it hard to engage in new areas. It takes courage to leap into new things and a lot of experimentation.

[2012] Only a couple of things I would add here. As an astute blog reader pointed out in my first post, sometimes you need to de-program before you can start enjoying retirement. Societal programming is a very powerful force and sometimes you need time to adapt to a slower more leisurely pace of life. Then you can start taking up new hobbies, or old ones, to keep that old nogging rocking. Investing still fulfills this role for me, even more so than 2 years ago. One thing that helped me was to go completely cold turkey from TV news, talking heads, etc…and that goes for most financial news media especially CNBC. Unlug, you’ll be happier. Surprisingly, technology has helped me stay informed, yet unplugged. My iPad, blogs, and twitter have been a huge boon in this regard.

[2014] Well, 9 years after leaving the 9-5 grind and 5 years on the road I can confidently say that I am fully de-programmed. I guess the only change for me here has been that the move to more quantitative investing has given me more time to do other things like cook more, do more long term investment research and macro-economics study (yes, I like these things), read more literature, etc…All good.

4. Physical/Health – I think being physically active helps in all areas of life but it certainly does impact your health. Also, in this age of expensive health care and insurance it is a key aspect of retirement especially as one ages. The healthier you are the less financial impact it will have on your retirement. The healthier you are the more you can do in retirement. So, I think its critical to have at least one physical activity/hobby that you love and engage in all the time. For my wife and I, its is hiking. We hike/walk 3-6 miles a day with our dog, without fail. We also are active in yoga, we run a bit, and do some strength training. Nutrition is a also big part of this for us.

[2012] No changed here except maybe I think its even more important than I first thought. I would also add to beware of conventional wisdom in particular standard medical, pharmaceutical treatments and nutritional advice. My wife and I are happy and healthier than ever following primal/paleo lifestyle for the last 4 years.

[2014] It’s just as important now as it was 2 years ago and it’s a big part of our life.

Retirement is not unlike any major transition in life. It takes time, patience, flexibility, and a little bit of effort. Pour all ingredients into a bowl, add an optimistic bright frame of mind and you have yourself a recipe for a happy and fulfilling retirement.

A better retirement through quantitative investing

September 22, 2014

Today I finally get around to doing something I mentioned way back in my first post on quantitative investing. Quant portfolios can help an investor handily beat the market over time and often with even lower risk. If that is the case then how could they impact safe withdrawal rates (SWRs) in retirement? Lets find out.

I’ve sort of already shown the effect of quant or automatic investing systems on SWRs in my posts on the various flavor of the IVY portfolios. For example, you can more than double your SWR with certain versions of the IVY portfolios. Beyond the basic buy and hold versions, the IVY portfolios are just different versions of quant systems in which whole asset classes and ETFs are used instead of individual stocks. In the IVY systems the quant metrics just happen to be trend following and momentum for the whole asset class. But I warned that the attractive SWRs from the IVY portfolios were too good to be true because the historical data did not encompass the worst period to retire in history, 1966, which defines the worst case SWRs. I want to extend that analysis of SWRs to quantitative systems using individual stocks I’ve discussed here before, namely the trending value portfolio and the combined consumer staples/utilities portfolio. These portfolios exhibit very high risk adjusted returns. Also, maybe the best part, is that we have historical data that encompasses 1966, the worst case retirement period which allows a very valid comparison to traditional retirement portfolios. OK, lets get to it.

First thing to be done is to re-run the standard stock, bond retirement portfolio (SP500) data for the period studied which is 1964 to 2013. Then do the same for the trending value (TV) portfolio and the consumer staples/utilities portfolio (XLP/XLU). Diversified portfolios are constructed with the US 10 year note. Below is a comparison of the SWRs for different stock bond allocations for the three portfolios.

SWRs for SP500 TV XLPXLU Portfolios Sep 2014

Although it’s not my purpose here, note that when you remove the great depression from the data set that even for the SP500 portfolios SWRs rise along with allocation to stocks. This is not the case when you include the great depression where the SWR falls off after its peak at 70% stocks 30% bonds. Probably a whole other topic for another day where I’ll muse about institutional learning, the rise of fiat monetary systems and the like. But for now lets just say there is not much incremental benefit for SWRs beyond 60/40. At 60/40 look at the increase in SWRs from both the quantitative portfolios; 6.39% SWR for the XLP/XLU portfolio and 7% SWR for the TV portfolio. Pretty darn good. But what about the two other retirement portfolio metrics I like to look at; maximum drawdown and average end wealth? I present those two tables below.

Max DD and AEW for SP500 TV XLPXLU Portfolios Sep 2014

MaxDD in the top table is the maximum drawdown, peak portfolio value to trough portfolio value, on an annual basis. It is the same as the worst year if there is only one down year. In the case of multiple down years it represents the compounding of those bad years after retirement withdrawals which is what matters most. $AEW is the Average Ending Wealth, or ending portfolio value, of all the 30 year retirement periods in the analysis. This is the value of the portfolio you could potentially bequeath to your family and/or charities. The quant portfolios deliver on these metrics as well. Those high SWRs in the first table come with lower drawdowns and more wealth on average across the board. Again great news across the board.

In the MaxDD and $AEW table I highlighted the 30% stocks, 70% bond rows for a good reason. The more and more I talk to retired investors the more I think that SWR is not the parameter that most retirees should try to maximize. Losses or drawdowns are what gives retired investors the most fits and more importantly is what most often derails their investment plans which leads to very poor investment results. Keeping that in mind I highlighted in the MaxDD table a level that I think most investors can tolerate, less than 10% peak to trough loss on a yearly basis. That level is at a 30% stock 70% bond allocation for the various portfolios. With the quant portfolios even at that conservative allocation level you can support an SWR of over 5% and at the same time end your retirement with an average wealth that is almost as great as a 100% stock allocation if you were just using the SP500 for your equity investments. This is an example of what Larry Swedore calls ‘low-beta, high tilt’ portfolios where in you use the bond allocation to control beta or risk (i.e. drawdowns) to a tolerable level and use a ’tilt’ to factors that increase return such as small cap, value, and momentum. This is just one example. You can choose your own optimal allocation based on your preferences.

In summary, quantitative portfolios can significantly improve the important metrics of retirement portfolios; SWRs, maximum drawdown or loss, and average ending wealth. Or at a minimum they can vastly improve the odds of a successful retirement even at very conservative SWRs or equity allocations.

The flip side of a successful retirement: spending

September 17, 2014

Most of the ink spilled in talking about retirement is limited to the investment side of the equation. How much do you need for retirement? How much can you withdraw from your portfolio in retirement? How should I invest my retirement assets? And obviously, all these questions are critical. But just as important and not talked about as often is the amount of spending in retirement. I’ll touch on some of my thoughts on this topic and my personal experience.

A few weeks ago I was reminded of an old saying, ‘The easiest way to double your money is to take it out of your pocket, fold it in half, and put it back in your pocket’. Another one I like goes something like, ‘a dollar not spent is a 100% guaranteed return on your money’. These are somewhat old school thoughts. It reminds me of how my grandparents funded their retirement with basically a 100% cash allocation and tight control on spending. Just getting them into bank CDs was a major multi year effort. However, there is a ton of wisdom in some old school thoughts. And spending in retirement is just as important as investing in retirement. The three aspects of spending in retirement are the absolute level of spending, the yearly change in spending required to maintain the same lifestyle, and the amount of flexibility in the spending level. Here I want to focus on the absolute level of spending.

Your spending level in retirement can be a lot less than what most retirement resources tell you. The typical recommendation is to plan for 85% to 100% of your pre-retirement spending. Obviously, this is highly individual but I think its important to point out that you can have an amazing retirement by spending a lot less than you did pre-retirement. At least that has been my experience. Nina and I spend approximately half of what we did before we left our careers, almost nine years after the fact. Below is our level of spending by year as a percentage of our pre-retirement spending. 2005 was our last year of pre-retirement spending so that is the base year.

Change from pre retirement spending levels sep 2014


As you can see it fluctuates quite a bit but the general trend has been down. And our quality of life is infinitely higher. Not working in the traditional sense opens up a host of possibilities to spend less. For example, we spend less in “rent” (RV camping fees plus fuel) than we spent on association fees for our condo in San Francisco. And don’t even ask me about property taxes. Working has an implied cost that is commonly overlooked (clothes, commuting, etc…). When you remove the costs and constraints of working it can translate into a needing lot less to retire than if you planned for 100% of pre-retirement spending. Some times less is truly more. This is a huge topic and other people cover it a lot better than I can give it time. A good resource and community on spending less can be found at Mr Money Mustache. How would your life decisions change if you could spend half of what you spend now?

Once you have the absolute level of spending down then the task moves to managing the change in spending every year and the surprises that inevitably come down the line to throw your plans into the air. Anyone notice 2009 in the table above? That was not really a surprise but in late 2008 we decided to move back from Hong Kong to the US. The surprise was the sticker shock from the cost of the move. What better time to be flexible, right? I took a job in the US and negotiated a decent relocation allowance that paid for our move back. I stayed in the job for just less than year and during that time we lived the high life and started planning our RV adventure. The increase in spending from 2008 to 2009 was pretty much covered by my salary (I still withdrew from my retirement assets that year but it was a small percentage). In 2010 we moved into the RV and the rest is history so to speak. What I think is key here is that you have more control and flexibility than you think. If there is another big surprise down the road whether it be from a big spending increase or a big portfolio loss I have the flexibility to cut spending and/or increase income.

In summary, you don’t need to spend as much in retirement as the common wisdom suggests. This also means you don’t need as much to retire as well. Controlling spending is as big a part of successful retirement as the investment side of the equation. You have more control and flexibility than is commonly thought.

Understanding modern retirement calculators

August 31, 2014

In today’s post I want to explain and demonstrate how modern retirement calculators work. There are two basic ways to calculate how much you can safely withdraw from your portfolio in retirement; looking backwards using historical data for past retirees and looking forward using possible future investment returns. On this blog I’ve pretty much only described the historical safe withdrawal rate (SWR) approach. That’s where the 4% SWR number comes from that you hear talked about all the time. Modern retirement calculators do not use this approach. They use a forward looking approach called Monte-Carlo analysis to come up with their SWRs. Lets see how these calculators work.

What’s wrong with using historical data to come up with SWRs? The problem is history only represents one outcome of all the possible future paths from that previous point. If you were back in 1966 looking forward to a 30 year retirement the actual outcome of your 30 year retirement period, which happened to become the worst in history, was only one of many possibilities. Modern retirement calculators eliminate this drawback by looking at many many possible future retirement outcomes. That’s the fundamental difference. The rest is calculation details. How do they do this? They assume that future investment returns follow some probability distribution, since the future is fundamentally indeterminate and probabilistic. So, for example, they assume that future investment returns are normally distributed (they also use some really fancy distributions like multi-variate log normal but the results are similar), i.e. follow a bell curve. They then randomly generate a time series of investment returns and use those investment returns to calculate what the SWR would be in each of those random series of returns. Since they can’t do this for the infinite variety of possible returns they usually stop at a sufficiently large number that generates statistically robust results. The generally accepted large enough number for these retirement calculators is 10,000 trials.

Now, here is the catch with these retirement calculators. They still involve some kind of bias or human forecasting under this seemingly unbiased random robust scientific method. For those assumed normal distributions  you still need to pick a mean and a standard deviation to generate those random investment returns. And you still need to forecast inflation as well. You can’t model all possible potential future outcomes. Confused yet?

It’s really pretty simple, it’s just the calculations that get intense. I put together a simple retirement calculator in excel to illustrate how this is done. In one excel file I generated 1,000 random series of 30 year investment returns (note: every time you open, save, or make any changes to this file the random numbers change, unless you turn off automatic calc in options). I generated stock and bond returns independently. I then copied these results to another excel file where I did the work of calculating the SWR for those 1,000 random simulations. In this first pass I use the historical mean and standard deviations for US stocks and US 10 year government bonds from 1929 through 2013. I also used historical inflation. And this leads to the next important observation regarding retirement calculators. All of them define a successful SWR to one that has an 80% to 85% success rate. In a 10,000 trial simulation that means 1,500 to 2,000 of the possible time series of investment returns result in failure, i.e. running out of money. It’s just that those cases are lower probability events. Yet still possible. Using an 85% success rate my simple model yields and SWR of 3.92% for a 50/50 stock bond allocation. Pretty close to the historical SWRs for such a simple model.

But none of the modern retirement calculators I’ve seen use historical returns in their calculators. They all use a return forecast that is significantly lower than historical returns have been. I think the simplest and best retirement calculator is the one from Vanguard. I like it because there is no need for a ton of inputs on the user’s part. It just generates the SWR based on the retirement period and one of three asset allocations. All the gory details are behinds the scenes. Their future return assumptions are updated once a year and explained in the Vanguard Capital Markets Model. It’s well worth the read. Basically, they use diversified portfolio returns of 3-5% real going forward, less than returns have been in the past. For a 30 yr retirement period and a moderate asset allocation their model yields and SWR of 3.8%. I used these lower future expected returns in my simple model and that yielded an SWR of 3.30%. You can access those files here and here.

At the end of all this fancy analysis we have a tool that tells us that future SWRs will be lower than the past because we are forecasting future returns to be lower than historical returns. And specifically lower than the 30 year retirement period that started in 1966 which is what gave us the worst case historical SWR to begin with. Seems kind of obvious when you put it that way. So, basically this all relies on a forecast of the future which are notoriously inaccurate. But its the best tool we have. From today’s valuation levels and interest rates it is possible the SWRs will be slightly to a good deal lower than 4%. But they may not be.

That pretty much sums up how modern retirement calculators work. Now you can at least use these tools with an understanding of what’s under the hood. You can even generate your own models if you want.

Note: the T Rowe Price retirement calculator is another very popular one. I find the added inputs and complexity unnecessary.

The impact of realistic spending on your retirement

May 28, 2014

In a post last week I showed that for the majority of retirees the standard recommended spending model in retirement does not match reality. Spending  in retirement actually grows by less than inflation over time. In this post I want to show you how using a more realistic sending model impacts how much you can withdraw from your portfolio in retirement.

If we go back and use the same model we used to calculate SWRs, we can adjust annual spending to see the impact of using a more realistic spending model on SWRs. For this post I simply changed the annual spending adjustment in retirement to grow by 1% less than inflation during the 30 year retirement periods (-1% per year real spending). This is actually pretty conservative compared to the actual retiree data.

Second, I took at look at combining a realistic spending model with a flexible spending model I’ve discussed in the past. The Floor Ceiling method basically allows spending adjustments in retirement based on the performance of the portfolio. For this post I used a floor ceiling model with unlimited upside and a max floor of -10% to inflation adjusted spending.

The results are shown in the table below for 30 year retirement periods, a 70-30 SP500 10yr UST bond stock portfolio with data going back to 1929.

SWRs for base vs realistic vs fcm model may 2014

The standard retirement model says your SWR is 4.39% for this portfolio. By simply using a more realistic spending model the SWR for the portfolio goes up to 4.90% an increase of almost 12%. The FCM model with its flexible spending says your SWR is 4.84% for this portfolio. By combining both approaches the SWR for the portfolio goes up to 5.39%, an increase of over 22%! That’s a raise of 22% per year in retirement simply by being more realistic and flexible. Very powerful stuff.

For those still building for retirement the implications are perhaps even more impactful. The percentage increases in SWR are equivalent to a reduction in the amount you need to fund your retirement. If you can spend 22% more with these models in retirement it also means you would need 22% less to retire. That could translate into several years of work or no work in this case.



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