Biden vs. Trump Stock Markets: What the Charts Show
Bob Weeks October 11, 2026
These two charts compare the S&P 500’s performance under President Biden’s final 19 months in office against President Trump’s first 19 months of his second term. One plots the raw index values; the other indexes both periods to a common starting point of 100, making it possible to compare percentage growth side by side regardless of where the market started. Here’s a plain-language walkthrough of what each one shows.
Chart 1: the actual index values
The first chart tracks the S&P 500’s real closing values from July 2023 through July 2026 – roughly 4,300 at the start, climbing to around 7,500 by the end. The thin black line is the month-by-month close. The blue and red overlays are simple trend lines drawn on top of that same data: blue covers the final 19 months of Biden’s term, red covers the first 19 months of Trump’s second term.
The chart is really just showing the market’s trajectory continuing (or bending) across the presidential transition, using one continuous number line.
Chart 2: indexed to a common starting point
The second chart does something different. Instead of raw dollar values, it sets month 1 of each 19-month stretch equal to 100 and tracks percentage change from there – Biden’s final 19 months on one line, Trump’s first 19 months on the other, both starting from the same baseline regardless of what the actual S&P 500 level was at the time.
That’s the useful transformation: by the time Trump’s second term began, the index was already sitting far higher than it was at the start of Biden’s final stretch, so Chart 1 alone can’t easily answer “which period grew faster, relative to its own starting point?” Chart 2 can.
Reading it: the red (Trump) line dips early, down to about 93 by months 3 and 4, before recovering and running mostly ahead of the blue (Biden) line through the middle months. It dips again around month 13 and 14, and the two lines end up close together by month 19, with Biden’s line finishing slightly higher.
The bottom line
Both charts make a legitimate comparison, each answering a different question. Chart 1 shows where the index actually stood, which is useful for seeing the market’s real trajectory across the transition. Chart 2 strips out the absolute level and shows growth from each period’s own starting point, which is useful for comparing pace rather than dollar amounts. Read together, they give a fuller picture than either one alone.