Elections & Markets
How did the S&P 500 and the Dow Jones move in the weeks before and after US elections? Every presidential and midterm election since 1896, aligned on the reference close t0 (last close on or before election day) — and next to it the same weeks in years without an election, because early November tends to be a strong time for stocks anyway.
X axis = trading days relative to the reference close t0 (last close on or before election day). Y axis = change in % from t0 or from the start of the window. Line = mean, dashed = median, area = the range in which the middle half of the elections fell (25th–75th percentile, not a confidence band). Grey = the same weeks in the two adjacent years without an election — only elections for which both comparison years are complete, so its gap to the gold line can differ from the paired difference below. The main window 20/20 was fixed in advance; other settings are exploration. Click a table row to show a single election.
Every election
Before = change from the start of the window to the reference close t0, after = from t0 to the end of the window. Only elections with a price on every day of the chosen window are counted — so the number can change with the window.
Methodology — how it is calculated
Reference point
Everything is aligned on the last close on or before election day. US election results become known in the night after election day, so this close is the last one before the result. Until 1968 the New York Stock Exchange was closed on every election day, and in 1972, 1976 and 1980 still on presidential election days; in those years the reference point is the close of the day before. A late result (2000: decided only on 12 December) does not move the reference point.
Comparison with years without an election
For each election the two adjacent odd years are evaluated — there is no nationwide US election in those years. The reference date there follows the same rule (the Tuesday after the first Monday in November). The grey line first averages the two comparison years of an election and then across all elections for which both comparison years are complete. The gap to the grey line is a historical comparison, not an isolated election effect: the economy, rate decisions and other events play a part.
Data
Election dates and results are each confirmed by at least two sources (US National Archives, House and Senate). Daily closes from our own database. The Dow consisted of 12 stocks until 1916 and of 20 until 1928; the S&P 500 is a back-calculation before 1957, and there were Saturday sessions before 1953. A “trading day” here is one price row of the selected series.
What the page does not say
- No p-value. With about 30 elections per type and freely chosen windows, a significance statement would be misleading.
- Nothing about the party as the cause. The change-of-power filter shows a retrospective selection with small numbers.
- Nothing about the future. Every election takes place in a different environment.
Frequently asked questions
Do stocks rise after a US election?
On historical average, the S&P 500 and the Dow were higher a few weeks after US elections than on election day — but early November tends to be a strong time for stocks anyway. That is why the grey comparison line is shown next to it. The gap to that line is a historical difference, not an isolated election effect.
Why is the reference point the close on election day?
Because the result becomes known in the night after election day, so the election-day close is the last one before the result. If the exchange was closed on election day, the close of the day before is used.
How much does the winner matter?
The “change of power” filter shows how elections with and without a change differed. It is a retrospective selection — on the day before the election nobody knows the winner — and with few cases per group the page reports no significance.
Is this a trading signal?
No. The page is an analysis of historical price data, not a forecast and not investment advice. Past patterns do not guarantee future results.