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Last week, I showed why the “ultimate death cross” is not a bearish signal. But the methodology behind that signal – what’s known as a “golden-cross trigger” – can indeed offer a reliable guide to investors. And one can do even better with a simple improvement to the trigger that I have devised.
The basic golden-cross trigger occurs when the 50-day, short-term average of a stock or index moves above its 200-day, long-term average. I modify this slightly to get something I call the ”moving average crossover” (MAC) system, which I’ll explain in due course.
Its results are impressive. An asset allocation strategy based on the MAC system provided, on average, a 40% higher return than the basic golden-cross trigger would have offered. Historical investment results from this MAC system have been, on average, 2.4 times higher and less risky than a buy-and-hold (B&H) investment in an S&P 500 index fund. The strategy is easy to implement and should be useful for retirement accounts.
In appendix A are the probabilities calculated from likelihood ratios for market gains and losses following MAC signals; it shows why I selected the particular moving averages that I chose for my MAC system.
I used daily data from January 4, 1965 to July 6, 2012. Investment results are with dividends reinvested. For the S&P, dividend information comes from Robert Shiller’s S&P data series; reported dividends were reduced by 5% to account for fund fees. When not invested in the S&P 500 index fund, I assumed funds were held in the Vanguard GNMA fund (VFIIX) from its 1980 inception onwards, and before that I used a money market account paying interest at the Federal Funds Rate. For the calculation of moving averages I used trading days, not calendar days.
The investment strategy
My MAC system works as follows, with a buy signal and a sell signal triggering shifts from investment in the markets to the safer, money-market-fund-like reserve.
Buy signal for the S&P 500
- A buy signal occurs when the 34-day exponential moving average (EMA) of the S&P 500 becomes greater than 1.001 times the 200-day EMA. (See appendix B for calculation of the EMA.)
Sell signal for the S&P 500
- A sell signal occurs when the 40-day simple moving average (MA) of the S&P 500 crosses below the 200-day MA.
There were 28 buy signals from 1966 to 2012, the most recent occurring on January 3, 2012. Buy signals didn’t count when they occurred during the period while the previous buy signal was still in effect, which resulted in only 24 useable buy signals out of the 28 possible; they are listed in appendix C together with their corresponding sell signals.
There were 28 sell signals from 1966 to 2012, of which 23 followed a previous buy signal. The most recent occurred on August 12, 2011.
When a buy signal occurs, the whole investment goes into an S&P 500 index fund, and when a sell signal occurs all the funds are moved from the S&P 500 index fund to a GNMA fund. It’s that simple.
Investment results
To simulate this strategy over longer periods, I began with $1.00 in a GNMA fund (or a money market account, prior to 1980) on the first day of every year from 1966 to 2010. I then transferred the money to a S&P 500 index fund when the first buy signal occurred. I then calculated the terminal value for each year’s $1.00 investment, in all cases through July 6, 2012.
Starting with a dollar during each of the 45 years from 1966 to 2010, one would have invested a total of $45 cumulatively by the end. Summing the 45 terminal values, this strategy would have netted this dollar-per-year investor a tidy sum of $2,502. Following a B&H strategy in the S&P 500, one would have only $835, about a third as much. (The basic golden-cross system would have produced about two times more than the B&H strategy, but still a good deal less than the MAC system.)
The final value of the investment accrues in a few ways: from capital gains (or losses) following the model’s buy signals, reinvested dividends while in the stock market, and both the capital gains (or losses) and reinvested dividends from the GNMA investments (or interest from a money market account prior to 1980).
Had one made the first investment in January 1990, instead of 1966, he or she would have invested a total of $21 by now. The sum of the 21 terminal values to July 6, 2012 was $102, versus $53 for the B&H strategy in the S&P 500. (The basic golden-cross system in this case would have produced 1.61 times more than the B&H strategy in the S&P.)
The table below lists the internal rate of return (IRR) for the $1 annual investments obtained from the MAC system, the buy-and-hold strategy of the S&P 500, and from a money market account.
Modified golden-cross system: S&P500 returns with dividends reinvested - when not in S&P500, funds are invested in a GNMA fund with dividends reinvested. |
|
|
B&H money market at Fed Fund Rate |
B&H S&P500 |
modified golden cross MAC system |
B&H money market at Fed Fund Rate |
B&H S&P500 |
modified golden cross MAC system |
|
|
|
|
|
number of investments |
45 |
45 |
45 |
21 |
21 |
21 |
|
total invested |
45 |
45 |
45 |
21 |
21 |
21 |
|
sum of terminal values |
$124.17 |
$835.00 |
$ 2,502.34 |
$ 32.49 |
$ 52.52 |
$101.79 |
|
IRR |
3.82% |
9.88% |
13.13% |
2.05% |
7.17% |
11.95% |
for periodic investments |
max IRR |
|
15.66% |
13.79% |
|
15.66% |
11.95% |
min IRR |
|
3.81% |
9.04% |
|
3.81% |
9.04% |
average IRR |
2.23% |
8.10% |
11.79% |
1.28% |
6.33% |
10.17% |
standard deviation |
|
2.68% |
1.70% |
|
2.95% |
0.90% |
Sharpe ratio |
|
2.19 |
5.64 |
|
1.71 |
9.84 |
|
period |
1966 – 2012 |
1990 - 2012 |
A common measure known as the Sharpe ratio, applied to the data above, underscores the effectiveness of MAC. The Sharpe ratio of an investment is calculated by subtracting the risk-free IRR (which is the average IRR of a money market account earning interest at the Federal Funds Rate) from the investment’s average IRR, then dividing the result by the standard deviation of the investment’s average IRR. The greater an investment’s Sharpe ratio, the better its risk-adjusted performance. The higher Sharpe ratio for the MAC system indicates that its superior performance relative to a B&H strategy in the S&P500 was achieved with less risk. (See appendix D for all yearly returns.)
Figures 1 and 2 show that the MAC system generated sell signals prior to major market downturns. It avoided the 1987 crash and major recessions, and its buy signals ensured that people were invested when the market was moving up.
Current situation
Figure 3 shows the current data in more detail and includes graphs of the buy- and sell-spreads. Since the last buy signal, on January 3, 2012, the S&P had gained about 8.5% through July 27, 2012. This is not surprising, because the probability of the market being higher during one week following a seven-month period after a buy signal from MAC is 92.6%.
The sell-spread (the red graph depicting the difference between the 40-day MA of the S&P and the 200-day MA) has been steadily declining from a high of 116 in May to the current level of about 20, where it appears to be forming a trough. A sell signal will only emerge when and if this signal moves below zero.
Conclusion
Anybody who still believes that a buy-and-hold system provides the best possible returns is seriously mistaken. Life-cycle and target-date funds, which are touted as safe investments, are badly flawed, as they are nothing but buy-and-hold investments of bond and stock funds. Buy-and-hold for any investment not paying substantial dividends works only in bull markets; it is a loss maker in bear markets.
The technical timing model described above is simple and rule-based. Its historic internal rate-of-return of more than 10% should be quite acceptable to investors. There is obviously no guarantee that the past performance will prevail into the future, but the MAC system has consistently outperformed a buy-and-hold investment in the S&P with considerably less investment risk, and, what is more, it is easy to implement by anyone who can calculate the model’s four required moving averages. (Those who can’t can subscribe to my free weekly model updates.)
My other stock market model, as described in my article “Improving on Buy and Hold: Asset Allocation using Economic Indicators”, provided better returns than the MAC system. When following that model’s signals, the sum of the 45 terminal values for the annual dollar investment dating back to 1966 was $7,824, and the sum of the 21 terminal values for annual investment of $1.00 since 1990 was $143, with associated IRRs of 16.46% and 14.32%, respectively, for the two periods. However, this model is not easily replicated, whereas the MAC system is simple to set up and maintain. No outside guidance is needed, nor does one have to keep up with the ever-growing, never-ending stream of financial news – the only required input is the S&P 500 index.
Appendix A
Probabilities for market gains and losses
The moving averages for the MAC system were determined for the highest probability of success using likelihood ratios. This was done by simultaneously maximizing the number of signals and the likelihood ratio positive after a predetermined investment period.
For the buy signal, I tested how often the S&P was higher during one week following a one-year investment period in the stock market. The table below shows the results for the basic and modified golden-cross systems. It is interesting that the probability of the market being higher during one week following a one-year period at any point in time from 1965 onwards is already a quite high 72.9%. Entering the market after a buy signal from the MAC system raises this probability to 88.5% and using the basic system the probability increases to a slightly lower 82.6%. These are good odds to make money.
|
modified golden-cross buy signal |
basic golden-cross buy signal |
signals with gain = |
23 |
19 |
signals with loss = |
3 |
4 |
pre-test probability = |
0.729 |
0.729 |
Likelihood Ratio +ve = |
29.62 |
16.35 |
post-test probability = |
0.885 |
0.826 |
For the sell signal I tested how often the S&P was lower during one week one year after the sell signal. The table below shows the results for the basic and modified golden-cross systems.
|
modified golden-cross sell signal |
basic golden-cross sell signal |
signals with gain = |
16 |
15 |
signals with loss = |
11 |
9 |
pre-test probability = |
0.314 |
0.314 |
Likelihood Ratio +ve = |
2.83 |
2.45 |
post-test probability = |
0.407 |
0.375 |
The probability of the market being lower during one week following a one-year period at any point in time from 1965 onwards is only 31.4%. After a sell signal from the MAC system the probability increases to 40.7%, and using the basic system the probability increases to a slightly lower 37.5%. The probability of a market decline after a sell signal becomes 1.3 times greater than the pre-test probability, but signals with subsequent gains still outnumber signals with subsequent losses as one can see from the table above.
From this analysis it is evident that the MAC system has the better chances than the basic system to profit from the probable market direction. This is also reflected by the returns, which are about 40% better for the MAC system than for the basic one.
Appendix B
Exponential moving average
The exponential moving average (EMA) is a filter that applies weighting factors to the observed data values. The weighting for each older data point decreases exponentially, never reaching zero.
The formula used for calculating the EMA is
EMAtoday = EMAyesterday + α × (valuetoday - EMAyesterday)
The coefficient α represents the degree of weighting decrease, a constant smoothing factor between 0 and 1. A higher α discounts older observations faster. Alternatively, α may be expressed in terms of N time periods, where α = 2/(N+1). For example, N = 200, as used for the long EMA of the S&P500, provides a smoothing factor of 0.010, and N = 34 for the short EMA has smoothing factor of 0.057. The “long” and “short” refers to the N time periods used in the calculation of the smoothing factor for the EMA.
Appendix C
Buy and sell signals for a continuous investment since 1966
Signal Nr. |
BUY Dates |
SELL Dates |
S&P500 on BUY Date |
S&P500 on Sell Date |
S&P500 % change |
S&P500 with dividends % change |
1 |
4/7/66 |
4/14/66 |
91.76 |
91.87 |
0.12% |
0.12% |
2 |
1/24/67 |
2/21/68 |
86.51 |
91.24 |
5.47% |
7.62% |
3 |
4/18/68 |
3/10/69 |
97.08 |
98.99 |
1.97% |
3.69% |
4 |
4/25/69 |
6/25/69 |
101.72 |
97.01 |
-4.63% |
-4.40% |
5 |
10/15/70 |
9/20/71 |
84.65 |
99.68 |
17.76% |
20.24% |
6 |
12/21/71 |
4/11/73 |
101.8 |
112.68 |
10.69% |
13.44% |
7 |
10/18/73 |
11/21/73 |
110.01 |
99.76 |
-9.32% |
-9.10% |
8 |
2/28/75 |
11/17/76 |
81.59 |
100.61 |
23.31% |
31.23% |
9 |
5/8/78 |
12/4/78 |
96.19 |
96.15 |
-0.04% |
2.81% |
10 |
1/19/79 |
4/11/80 |
99.75 |
103.79 |
4.05% |
10.69% |
11 |
5/27/80 |
6/25/81 |
111.4 |
132.81 |
19.22% |
25.28% |
12 |
9/14/82 |
1/31/84 |
123.1 |
163.41 |
32.75% |
41.10% |
13 |
8/17/84 |
11/5/86 |
164.14 |
246.58 |
50.23% |
63.36% |
14 |
6/24/88 |
2/20/90 |
273.79 |
327.99 |
19.80% |
26.22% |
15 |
2/1/91 |
4/15/94 |
343.05 |
446.18 |
30.06% |
42.07% |
16 |
8/17/94 |
12/28/94 |
465.17 |
460.86 |
-0.93% |
-0.05% |
17 |
1/17/95 |
9/18/98 |
470.05 |
1,020.09 |
117.02% |
132.65% |
18 |
11/2/98 |
10/23/00 |
1111.6 |
1,395.78 |
25.56% |
28.37% |
19 |
5/22/03 |
8/12/04 |
931.87 |
1,063.23 |
14.10% |
16.33% |
20 |
8/25/04 |
7/10/06 |
1,104.96 |
1,267.34 |
14.70% |
18.39% |
21 |
8/2/06 |
12/13/07 |
1,277.41 |
1,488.41 |
16.52% |
19.17% |
22 |
8/3/09 |
6/25/10 |
1,002.63 |
1,076.76 |
7.39% |
9.17% |
23 |
8/5/10 |
8/12/11 |
1,125.81 |
1,178.81 |
4.71% |
6.57% |
24 |
1/3/12 |
- |
1,277.06 |
- |
- |
- |
Appendix D
Comparison of returns for Buy-and-Hold S&P500 and Modified Golden-Cross MAC System with
dividends reinvested to July 6, 2012 |
$1.00 invest on first day of year |
nr. of signals with gains and losses |
terminal value of $1.00 |
compound average annual growth rate |
signal absolute return |
relative perform-
ance |
sum of terminal values |
internal rate of return |
gain |
loss |
B&H
S&P
$ |
MAC
$ |
B&H
S&P
% |
MAC
% |
worst
% |
best
% |
MAC
/
S&P |
B&H
S&P
$ |
MAC
$ |
B&H
S&P
% |
MAC
% |
1966 |
20 |
3 |
52.16 |
213.29 |
8.86 |
12.20 |
-9.10 |
132.65 |
4.09 |
835 |
2502 |
9.88 |
13.13 |
1967 |
19 |
3 |
58.44 |
205.76 |
9.34 |
12.40 |
-9.10 |
132.65 |
3.52 |
783 |
2289 |
9.97 |
13.24 |
1968 |
18 |
3 |
47.81 |
191.65 |
9.06 |
12.51 |
-9.10 |
132.65 |
4.01 |
724 |
2083 |
10.03 |
13.33 |
1969 |
17 |
3 |
43.66 |
184.48 |
9.05 |
12.72 |
-9.10 |
132.65 |
4.23 |
677 |
1892 |
10.13 |
13.42 |
1970 |
17 |
2 |
48.26 |
184.25 |
9.53 |
13.03 |
-9.10 |
132.65 |
3.82 |
633 |
1707 |
10.23 |
13.50 |
1971 |
16 |
2 |
46.92 |
150.31 |
9.70 |
12.81 |
-9.10 |
132.65 |
3.20 |
585 |
1523 |
10.30 |
13.55 |
1972 |
15 |
2 |
41.52 |
134.02 |
9.62 |
12.83 |
-9.10 |
132.65 |
3.23 |
538 |
1373 |
10.36 |
13.63 |
1973 |
15 |
2 |
35.35 |
130.01 |
9.43 |
13.09 |
-9.10 |
132.65 |
3.68 |
496 |
1239 |
10.44 |
13.72 |
1974 |
15 |
1 |
41.88 |
135.56 |
10.17 |
13.57 |
-0.05 |
132.65 |
3.24 |
461 |
1109 |
10.54 |
13.79 |
1975 |
15 |
1 |
57.13 |
126.02 |
11.37 |
13.74 |
-0.05 |
132.65 |
2.21 |
419 |
973 |
10.57 |
13.79 |
1976 |
14 |
1 |
41.71 |
98.31 |
10.74 |
13.37 |
-0.05 |
132.65 |
2.36 |
362 |
847 |
10.40 |
13.76 |
1977 |
14 |
1 |
33.80 |
94.93 |
10.40 |
13.65 |
-0.05 |
132.65 |
2.81 |
320 |
749 |
10.31 |
13.79 |
1978 |
14 |
1 |
36.59 |
91.37 |
10.97 |
13.95 |
-0.05 |
132.65 |
2.50 |
286 |
654 |
10.27 |
13.77 |
1979 |
13 |
1 |
34.48 |
87.00 |
11.12 |
14.23 |
-0.05 |
132.65 |
2.52 |
250 |
562 |
10.12 |
13.68 |
1980 |
12 |
1 |
29.22 |
80.65 |
10.92 |
14.43 |
-0.05 |
132.65 |
2.76 |
215 |
475 |
9.90 |
13.51 |
1981 |
11 |
1 |
22.15 |
61.28 |
10.31 |
13.92 |
-0.05 |
132.65 |
2.77 |
186 |
395 |
9.67 |
13.25 |
1982 |
11 |
1 |
23.39 |
56.94 |
10.86 |
14.14 |
-0.05 |
132.65 |
2.43 |
164 |
333 |
9.53 |
13.05 |
1983 |
10 |
1 |
19.31 |
37.35 |
10.53 |
13.02 |
-0.05 |
132.65 |
1.93 |
141 |
276 |
9.24 |
12.74 |
1984 |
10 |
1 |
15.80 |
33.98 |
10.14 |
13.13 |
-0.05 |
132.65 |
2.15 |
121 |
239 |
8.96 |
12.63 |
1985 |
9 |
1 |
14.92 |
26.25 |
10.30 |
12.59 |
-0.05 |
132.65 |
1.76 |
105 |
205 |
8.71 |
12.47 |
1986 |
9 |
1 |
11.36 |
21.68 |
9.58 |
12.28 |
-0.05 |
132.65 |
1.91 |
90.48 |
179 |
8.36 |
12.39 |
1987 |
9 |
1 |
9.60 |
19.69 |
9.25 |
12.36 |
-0.05 |
132.65 |
2.05 |
79.12 |
157 |
8.10 |
12.36 |
1988 |
9 |
1 |
9.14 |
19.33 |
9.42 |
12.81 |
-0.05 |
132.65 |
2.12 |
69.53 |
138 |
7.86 |
12.30 |
1989 |
8 |
1 |
7.87 |
16.42 |
9.15 |
12.61 |
-0.05 |
132.65 |
2.09 |
60.39 |
118 |
7.52 |
12.12 |
1990 |
8 |
1 |
6.00 |
14.31 |
8.26 |
12.52 |
-0.05 |
132.65 |
2.39 |
52.52 |
102 |
7.17 |
11.95 |
1991 |
8 |
1 |
6.21 |
12.97 |
8.84 |
12.62 |
-0.05 |
132.65 |
2.09 |
46.53 |
87.48 |
6.93 |
11.76 |
1992 |
7 |
1 |
4.77 |
9.85 |
7.89 |
11.77 |
-0.05 |
132.65 |
2.07 |
40.32 |
74.50 |
6.51 |
11.48 |
1993 |
7 |
1 |
4.44 |
9.21 |
7.92 |
12.02 |
-0.05 |
132.65 |
2.08 |
35.55 |
64.65 |
6.21 |
11.34 |
1994 |
7 |
1 |
4.04 |
8.71 |
7.81 |
12.37 |
-0.05 |
132.65 |
2.16 |
31.11 |
55.44 |
5.83 |
11.10 |
1995 |
7 |
0 |
3.99 |
8.77 |
8.20 |
13.16 |
6.57 |
132.65 |
2.20 |
27.07 |
46.73 |
5.37 |
10.69 |
1996 |
6 |
0 |
2.91 |
4.53 |
6.66 |
9.56 |
6.57 |
28.37 |
1.56 |
23.08 |
37.97 |
4.68 |
9.87 |
1997 |
6 |
0 |
2.37 |
4.31 |
5.70 |
9.84 |
6.57 |
28.37 |
1.82 |
20.17 |
33.43 |
4.22 |
9.86 |
1998 |
6 |
0 |
1.78 |
3.93 |
4.04 |
9.87 |
6.57 |
28.37 |
2.21 |
17.80 |
29.12 |
3.88 |
9.78 |
1999 |
5 |
0 |
1.39 |
3.16 |
2.43 |
8.86 |
6.57 |
19.17 |
2.28 |
16.02 |
25.19 |
3.81 |
9.66 |
2000 |
5 |
0 |
1.18 |
3.14 |
1.31 |
9.53 |
6.57 |
19.17 |
2.67 |
14.64 |
22.03 |
4.05 |
9.75 |
2001 |
5 |
0 |
1.25 |
2.82 |
1.93 |
9.39 |
6.57 |
19.17 |
2.26 |
13.46 |
18.89 |
4.54 |
9.69 |
2002 |
5 |
0 |
1.43 |
2.61 |
3.46 |
9.52 |
6.57 |
19.17 |
1.82 |
12.21 |
16.07 |
5.07 |
9.63 |
2003 |
5 |
0 |
1.85 |
2.42 |
6.64 |
9.67 |
6.57 |
19.17 |
1.31 |
10.78 |
13.46 |
5.43 |
9.49 |
2004 |
4 |
0 |
1.43 |
2.09 |
4.29 |
8.99 |
6.57 |
19.17 |
1.46 |
8.93 |
11.04 |
4.89 |
9.21 |
2005 |
3 |
1 |
1.29 |
1.77 |
3.47 |
7.81 |
-0.23 |
19.17 |
1.36 |
7.50 |
8.95 |
5.00 |
9.04 |
2006 |
3 |
1 |
1.24 |
1.71 |
3.28 |
8.51 |
-0.23 |
19.17 |
1.38 |
6.20 |
7.19 |
5.47 |
9.28 |
2007 |
2 |
0 |
1.07 |
1.51 |
1.21 |
7.76 |
6.57 |
9.17 |
1.42 |
4.97 |
5.48 |
6.32 |
9.26 |
2008 |
2 |
0 |
1.02 |
1.42 |
0.33 |
7.92 |
6.57 |
9.17 |
1.39 |
3.90 |
3.97 |
9.05 |
9.64 |
2009 |
2 |
0 |
1.61 |
1.32 |
14.40 |
8.13 |
6.57 |
9.17 |
0.82 |
2.89 |
2.55 |
15.66 |
10.16 |
2010 |
1 |
0 |
1.27 |
1.23 |
9.92 |
8.47 |
6.57 |
6.57 |
0.97 |
1.27 |
1.23 |
12.82 |
10.93 |
Georg Vrba is a professional engineer who has been a consulting engineer for many years. In his opinion, mathematical models provide better guidance to market direction than financial “experts.” He has developed financial models for the stock market, the bond market and the yield curve, all published in Advisor Perspectives. The models are updated weekly. If you are interested to receive theses updates at no cost send email request to [email protected].
Read more articles by Georg Vrba, P.E.