If you invested $100 in the S&P 500 at the beginning of 1920, you would have about $382.18 at the end of 1935, assuming you reinvested all dividends. This is a return on investment of 282.18%, or 8.74% per year.
This lump-sum investment beats inflation during this period for an inflation-adjusted return of about 457.92% cumulatively, or 11.34% per year.
If you used dollar-cost averaging (monthly) instead of a lump-sum investment, you'd have $426.80.
The graph below shows the performance of $100 over time if invested in an S&P 500 index fund. The returns assume that all dividends are automatically reinvested.
The nominal return on investment of $100 is $282.18, or 282.18%. This means by 1935 you would have $382.18 in your pocket.
However, it's important to take into account the effect of inflation when considering an investment and especially a long-term investment. You can convert S&P returns to their real (inflation-adjusted) value using an inflation calculation based on the U.S. Bureau of Labor Statistics Consumer Price Index (CPI).
In the case of the returns described above, the CPI in 1920 was 20.000 and the CPI in 1935 was 13.700.
The ratio between these CPIs describes how relative buying power of a dollar has changed over 15 years.
Adjusted for inflation, the $382.18 nominal end value of the original $100 investment would have a real return of roughly $457.92 in 1920 dollars. This means the inflation-adjusted return is 457.92% as opposed to the original 282.18%.
The table below shows the full dataset pertaining to a $100 investment, including gains and losses over the 192-month period between 1920 and 1935.
Note that data shown is the monthly average closing price. Returns include dividends.
Year
Month
Return (%)
Amount ($)
CPI
1920
1
-7.77%
92.23
19.30
1920
2
7.58%
99.22
19.50
1920
3
-0.30%
98.92
19.70
1920
4
-5.77%
93.21
20.30
1920
5
-1.20%
92.10
20.60
1920
6
0.42%
92.48
20.90
1920
7
-3.37%
89.36
20.80
1920
8
4.12%
93.04
20.30
1920
9
0.67%
93.67
20.00
1920
10
-4.53%
89.42
19.90
1920
11
-8.39%
81.92
19.80
1920
12
5.03%
86.04
19.40
1921
1
-0.11%
85.95
19.00
1921
2
-1.96%
84.27
18.40
1921
3
1.04%
85.14
18.30
1921
4
3.63%
88.24
18.10
1921
5
-7.43%
81.68
17.70
1921
6
0.31%
81.93
17.60
1921
7
-0.61%
81.43
17.70
1921
8
3.10%
83.95
17.70
1921
9
1.96%
85.60
17.50
1921
10
5.96%
90.69
17.50
1921
11
4.09%
94.40
17.40
1921
12
0.39%
94.77
17.30
1922
1
2.72%
97.35
16.90
1922
2
4.28%
101.51
16.90
1922
3
6.58%
108.19
16.70
1922
4
4.38%
112.93
16.70
1922
5
-0.47%
112.40
16.70
1922
6
1.19%
113.74
16.70
1922
7
4.24%
118.56
16.80
1922
8
3.07%
122.20
16.60
1922
9
2.67%
125.46
16.60
1922
10
-4.52%
119.79
16.70
1922
11
0.25%
120.09
16.80
1922
12
1.85%
122.31
16.90
1923
1
4.75%
128.12
16.80
1923
2
2.08%
130.78
16.80
1923
3
-3.04%
126.80
16.80
1923
4
-4.25%
121.41
16.90
1923
5
-3.31%
117.39
16.90
1923
6
-2.84%
114.06
17.00
1923
7
1.04%
115.24
17.20
1923
8
1.16%
116.58
17.10
1923
9
-0.94%
115.49
17.20
1923
10
3.54%
119.57
17.30
1923
11
3.92%
124.25
17.30
1923
12
3.79%
128.96
17.30
1924
1
0.95%
130.20
17.30
1924
2
-1.42%
128.35
17.20
1924
3
-1.79%
126.06
17.10
1924
4
0.17%
126.28
17.00
1924
5
2.42%
129.33
17.00
1924
6
5.16%
136.00
17.00
1924
7
3.93%
141.35
17.10
1924
8
-0.48%
140.67
17.00
1924
9
-0.81%
139.54
17.10
1924
10
6.08%
148.03
17.20
1924
11
5.87%
156.72
17.20
1924
12
4.58%
163.90
17.30
1925
1
1.29%
166.01
17.30
1925
2
-2.19%
162.38
17.20
1925
3
-0.61%
161.39
17.30
1925
4
3.67%
167.31
17.20
1925
5
2.24%
171.06
17.30
1925
6
3.22%
176.57
17.50
1925
7
1.79%
179.73
17.70
1925
8
2.74%
184.66
17.70
1925
9
3.73%
191.54
17.70
1925
10
3.53%
198.29
17.70
1925
11
2.04%
202.33
18.00
1925
12
1.93%
206.23
17.90
1926
1
0.56%
207.38
17.90
1926
2
-6.38%
194.14
17.90
1926
3
-2.35%
189.57
17.80
1926
4
1.15%
191.76
17.90
1926
5
5.22%
201.76
17.80
1926
6
4.66%
211.15
17.70
1926
7
4.39%
220.43
17.50
1926
8
1.94%
224.71
17.40
1926
9
-1.83%
220.59
17.50
1926
10
1.74%
224.43
17.60
1926
11
2.71%
230.50
17.70
1926
12
-0.24%
229.94
17.70
1927
1
2.37%
235.40
17.50
1927
2
1.97%
240.03
17.40
1927
3
2.88%
246.94
17.30
1927
4
3.87%
256.49
17.30
1927
5
1.70%
260.86
17.40
1927
6
2.62%
267.70
17.60
1927
7
5.73%
283.03
17.30
1927
8
6.06%
300.19
17.20
1927
9
-1.17%
296.69
17.30
1927
10
2.66%
304.57
17.40
1927
11
2.72%
312.85
17.30
1927
12
0.77%
315.25
17.30
1928
1
-0.83%
312.64
17.30
1928
2
5.75%
330.61
17.10
1928
3
6.66%
352.63
17.10
1928
4
3.44%
364.74
17.10
1928
5
-4.57%
348.09
17.20
1928
6
1.09%
351.89
17.10
1928
7
3.59%
364.53
17.10
1928
8
7.37%
391.41
17.10
1928
9
2.36%
400.64
17.30
1928
10
7.08%
429.01
17.20
1928
11
0.70%
431.99
17.20
1928
12
7.69%
465.22
17.10
1929
1
0.81%
469.00
17.10
1929
2
2.05%
478.61
17.10
1929
3
-0.30%
477.17
17.00
1929
4
1.80%
485.74
16.90
1929
5
2.20%
496.44
17.00
1929
6
9.20%
542.11
17.10
1929
7
5.96%
574.41
17.30
1929
8
4.24%
598.79
17.30
1929
9
-10.32%
536.96
17.30
1929
10
-26.19%
396.33
17.30
1929
11
4.37%
413.66
17.30
1929
12
1.83%
421.22
17.20
1930
1
6.64%
449.17
17.10
1930
2
4.12%
467.69
17.00
1930
3
6.69%
498.96
16.90
1930
4
-5.65%
470.77
17.00
1930
5
-9.77%
424.77
16.90
1930
6
-1.76%
417.30
16.80
1930
7
-0.90%
413.56
16.60
1930
8
0.34%
414.98
16.50
1930
9
-13.37%
359.49
16.60
1930
10
-6.80%
335.05
16.50
1930
11
-6.19%
314.32
16.40
1930
12
3.56%
325.50
16.10
1931
1
8.14%
351.99
15.90
1931
2
2.38%
360.37
15.70
1931
3
-9.08%
327.65
15.60
1931
4
-9.16%
297.63
15.50
1931
5
-2.68%
289.66
15.30
1931
6
3.86%
300.83
15.10
1931
7
-2.49%
293.36
15.10
1931
8
-14.37%
251.21
15.10
1931
9
-12.75%
219.18
15.00
1931
10
2.05%
223.68
14.90
1931
11
-18.10%
183.19
14.70
1931
12
-0.85%
181.64
14.60
1932
1
-0.05%
181.55
14.30
1932
2
1.14%
183.62
14.10
1932
3
-23.22%
140.98
14.00
1932
4
-11.31%
125.03
13.90
1932
5
-12.39%
109.53
13.70
1932
6
6.18%
116.31
13.60
1932
7
51.35%
176.04
13.60
1932
8
10.37%
194.28
13.50
1932
9
-13.22%
168.61
13.40
1932
10
-0.34%
168.04
13.30
1932
11
-2.64%
163.61
13.20
1932
12
4.57%
171.08
13.10
1933
1
-11.27%
151.81
12.90
1933
2
0.33%
152.31
12.70
1933
3
11.24%
169.44
12.60
1933
4
29.32%
219.11
12.60
1933
5
17.58%
257.64
12.60
1933
6
8.46%
279.44
12.70
1933
7
-4.64%
266.47
13.10
1933
8
-0.48%
265.18
13.20
1933
9
-9.38%
240.31
13.20
1933
10
2.80%
247.05
13.20
1933
11
2.32%
252.78
13.20
1933
12
6.08%
268.16
13.20
1934
1
7.75%
288.94
13.20
1934
2
-4.80%
275.08
13.30
1934
3
2.02%
280.63
13.30
1934
4
-9.83%
253.06
13.30
1934
5
1.70%
257.36
13.30
1934
6
-4.36%
246.16
13.40
1934
7
-3.51%
237.50
13.40
1934
8
-2.01%
232.73
13.40
1934
9
1.21%
235.55
13.60
1934
10
3.21%
243.11
13.50
1934
11
1.06%
245.68
13.50
1934
12
0.40%
246.68
13.40
1935
1
-2.62%
240.22
13.60
1935
2
-5.93%
225.97
13.70
1935
3
7.94%
243.91
13.70
1935
4
8.27%
264.07
13.80
1935
5
4.17%
275.09
13.80
1935
6
5.60%
290.50
13.70
1935
7
7.10%
311.13
13.70
1935
8
2.43%
318.71
13.70
1935
9
2.99%
328.22
13.70
1935
10
9.71%
360.09
13.70
1935
11
0.29%
361.15
13.80
1935
12
5.82%
382.18
13.80
Click to show 174 more rows
Remember, returns are based on the average closing price across the entire month. Some losses are offset by dividend returns.
Dollar-cost averaging
Dollar-cost averaging is an alternative to investing the full lump-sum of $100.00 up-front. Instead, the capital is invested over a period of time.
Consider a strategy in which $100.00 was invested in the S&P 500 over a period of no more than 24 months beginning in 1920. This would result in a final amount of $426.80, including dividend reinvestments. In this particular case, dollar-cost average returns are greater than the returns of a lump-sum investment (which ends with $382.18).
Year
Month
Contribution ($)
Amount ($)
1920
1
4.16
3.82
1920
2
4.16
8.56
1920
3
4.16
12.66
1920
4
4.16
15.83
1920
5
4.16
19.72
1920
6
4.16
23.96
1920
7
4.16
27.15
1920
8
4.16
32.58
1920
9
4.16
36.96
1920
10
4.16
39.24
1920
11
4.16
39.73
1920
12
4.16
46.07
1921
1
4.16
50.15
1921
2
4.16
53.23
1921
3
4.16
57.96
1921
4
4.16
64.35
1921
5
4.16
63.39
1921
6
4.16
67.74
1921
7
4.16
71.43
1921
8
4.16
77.91
1921
9
4.16
83.65
1921
10
4.16
93.01
1921
11
4.16
101.13
1921
12
4.32
105.83
1922
1
-
108.71
1922
2
-
113.36
1922
3
-
120.82
1922
4
-
126.11
1922
5
-
125.52
1922
6
-
127.02
1922
7
-
132.40
1922
8
-
136.47
1922
9
-
140.10
1922
10
-
133.78
1922
11
-
134.11
1922
12
-
136.59
1923
1
-
143.08
1923
2
-
146.05
1923
3
-
141.61
1923
4
-
135.59
1923
5
-
131.10
1923
6
-
127.38
1923
7
-
128.70
1923
8
-
130.19
1923
9
-
128.97
1923
10
-
133.53
1923
11
-
138.76
1923
12
-
144.02
1924
1
-
145.40
1924
2
-
143.34
1924
3
-
140.78
1924
4
-
141.02
1924
5
-
144.43
1924
6
-
151.88
1924
7
-
157.85
1924
8
-
157.10
1924
9
-
155.83
1924
10
-
165.31
1924
11
-
175.01
1924
12
-
183.04
1925
1
-
185.39
1925
2
-
181.34
1925
3
-
180.24
1925
4
-
186.85
1925
5
-
191.03
1925
6
-
197.19
1925
7
-
200.71
1925
8
-
206.21
1925
9
-
213.90
1925
10
-
221.44
1925
11
-
225.95
1925
12
-
230.30
1926
1
-
231.59
1926
2
-
216.81
1926
3
-
211.70
1926
4
-
214.15
1926
5
-
225.32
1926
6
-
235.81
1926
7
-
246.17
1926
8
-
250.95
1926
9
-
246.35
1926
10
-
250.63
1926
11
-
257.41
1926
12
-
256.79
1927
1
-
262.88
1927
2
-
268.05
1927
3
-
275.77
1927
4
-
286.43
1927
5
-
291.31
1927
6
-
298.96
1927
7
-
316.07
1927
8
-
335.24
1927
9
-
331.33
1927
10
-
340.13
1927
11
-
349.37
1927
12
-
352.06
1928
1
-
349.14
1928
2
-
369.20
1928
3
-
393.80
1928
4
-
407.33
1928
5
-
388.73
1928
6
-
392.97
1928
7
-
407.08
1928
8
-
437.10
1928
9
-
447.41
1928
10
-
479.10
1928
11
-
482.43
1928
12
-
519.54
1929
1
-
523.75
1929
2
-
534.49
1929
3
-
532.88
1929
4
-
542.45
1929
5
-
554.40
1929
6
-
605.40
1929
7
-
641.47
1929
8
-
668.70
1929
9
-
599.65
1929
10
-
442.60
1929
11
-
461.96
1929
12
-
470.39
1930
1
-
501.61
1930
2
-
522.29
1930
3
-
557.22
1930
4
-
525.73
1930
5
-
474.37
1930
6
-
466.02
1930
7
-
461.84
1930
8
-
463.43
1930
9
-
401.46
1930
10
-
374.16
1930
11
-
351.01
1930
12
-
363.50
1931
1
-
393.08
1931
2
-
402.44
1931
3
-
365.90
1931
4
-
332.38
1931
5
-
323.48
1931
6
-
335.95
1931
7
-
327.61
1931
8
-
280.53
1931
9
-
244.77
1931
10
-
249.79
1931
11
-
204.58
1931
12
-
202.84
1932
1
-
202.75
1932
2
-
205.06
1932
3
-
157.44
1932
4
-
139.62
1932
5
-
122.32
1932
6
-
129.89
1932
7
-
196.59
1932
8
-
216.97
1932
9
-
188.29
1932
10
-
187.66
1932
11
-
182.71
1932
12
-
191.06
1933
1
-
169.53
1933
2
-
170.10
1933
3
-
189.22
1933
4
-
244.70
1933
5
-
287.72
1933
6
-
312.07
1933
7
-
297.58
1933
8
-
296.14
1933
9
-
268.37
1933
10
-
275.89
1933
11
-
282.29
1933
12
-
299.47
1934
1
-
322.68
1934
2
-
307.19
1934
3
-
313.40
1934
4
-
282.60
1934
5
-
287.41
1934
6
-
274.89
1934
7
-
265.23
1934
8
-
259.91
1934
9
-
263.05
1934
10
-
271.49
1934
11
-
274.37
1934
12
-
275.48
1935
1
-
268.26
1935
2
-
252.36
1935
3
-
272.39
1935
4
-
294.90
1935
5
-
307.21
1935
6
-
324.41
1935
7
-
347.46
1935
8
-
355.91
1935
9
-
366.54
1935
10
-
402.13
1935
11
-
403.32
1935
12
-
426.80
Click to show 174 more rows
Data Sources
The information on this page is derived from Robert Shiller's book, Irrational Exuberance and the accompanying dataset, as well as the U.S. Bureau of Labor Statistics' monthly CPI logs.
Note that S&P index value for the current quarter is based on a moving average of closing prices, per Robert Shiller's methodology. The inflation data used is based on annual CPI averages.
About the author
Ian Webster is an engineer and data expert based in San Mateo, California. He has worked for Google, NASA, and consulted for governments around the world on data pipelines and data analysis. Disappointed by the lack of clear resources on the impacts of inflation on economic indicators, Ian believes this website serves as a valuable public tool. Ian earned his degree in Computer Science from Dartmouth College.
