Weirdly reminiscent of how then-President Bill Clinton went up in the polls after the Monica Lewinsky scandal, former President Donald Trump received a bump in various prediction markets following both his Thursday, March 30th indictment and Tuesday, April 4th arraignment.
But it wasn’t just the prediction markets. In different Ipsos polls taken before and after his arraignment, Trump’s support among 2024 Republican primary voters increased by 10 points (48% to 58%). The Trump campaign raised more money around their candidate’s indictment than his candidacy announcement. A former President of the United States being charged with felonies and fingerprinted had the opposite effect of what one might expect.
Even more weird, as Trump went up in the polls and prediction markets his favorability went down. FiveThirtyEight’s Trump favorability average was at its second-lowest point ever (37.4%) on April 8th, down 3.6 percentage points from one week prior and down 3.9 points from two weeks earlier.
Below are the probabilities of Trump winning the republican 2024 Presidential nomination on three real-money prediction markets (Polymarket, Insight Prediction, and PredictIt), two bookmakers (Bet365 and Betfred), one betting exchange (Smarkets), one forecasting platform (Metaculus), and one play-money prediction market (Manifold). To measure the impact of each event on Trump’s chances, we’re comparing Saturdays before and after the indictment (March 25th and April 1st) and arraignment (April 1st and April 8th).
Before and after the indictment
| Platform | ID | Trump Yes 3/25 | Trump Yes 4/1 | Net +/- |
| Polymarket | 0xf810652Ca2F32CECF67c71adFB534b98B567F344 | $0.5918 | $0.6015 | +$0.0097 |
| Insight Prediction | 12448 | $0.48 | $0.55 | +$0.07 |
| PredictIt | 7053 | $0.42 | $0.42 | – |
| Smarkets | 41936834 | 54.35% | 56.18% | +1.83% |
| Bet365 | oddschecker | 54.55% | 60.00% | +5.45% |
| Betfred | oddschecker | 52.38% | 57.89% | +5.51% |
| Manifold Markets | TWlja0JyYW5zZmllbGQ | 42% | 43% | +1% |
| Metaculus | 11370 | 44% | 44% | – |
Before and after the arraignment
| Platform | ID | Trump Yes 4/1 | Trump Yes 4/8 | Net +/- |
| Polymarket | 0xf810652Ca2F32CECF67c71adFB534b98B567F344 | $0.6015 | $0.6145 | +$0.0135 |
| Insight Prediction | 12448 | $0.55 | $0.57 | +$0.02 |
| PredictIt | 7053 | $0.42 | $0.48 | +$0.06 |
| Smarkets | 41936834 | 56.18% | 57.47% | +1.29% |
| Bet365 | oddschecker | 60.00% | 61.90% | +1.90% |
| Betfred | oddschecker | 57.89% | 60.00% | +2.11% |
| Manifold Markets | TWlja0JyYW5zZmllbGQ | 43% | 46% | +3% |
| Metaculus | 11370 | 44% | 55% | +9% |
A few observations:
- On March 25th, only three of eight platforms had Trump’s chances above 50%. By April 8th, six had Trump’s chances above 50%, with the exceptions being Manifold and PredictIt.
- The two platforms with no change from the indictment (PredictIt and Metaculus) were the two with the largest increases following the arraignment.
- All eight platforms showed a net increase in Trump’s chances after the arraignment.
- Real-money platforms tended to a larger bump from the arraignment than the indictment.
- On April 8th, the five non-US platforms (Bet 365, Polymarket, Betfred, Insight, and Smarkets) gave Trump the highest chances of winning the GOP nomination following the arraignment.
Prediction markets can be used to quantify conventional wisdom. There’s no psychic powers in aggregating a crowd’s opinion, but crowds have been shown to be effective at predicting and forecasting under certain conditions. Increases in Trump’s chances in the different prediction markets and bookmakers doesn’t mean he’s guaranteed to win the Republican nomination, it just indicates people forecasting or gambling on these platforms perceive these two events to have increased his chances.
And we should note that these markets are not asking about Trump being elected President again, just whether or not he will win the 2024 Republican nomination. In that context it makes more sense for Trump to increase his probabilities in the prediction markets and Republican primary polls at the same time his overall favorability is dropping; these are two different electorates.
Polymarket is a decentralized prediction market available outside the U.S. Donald Trump “Yes” prices were captured from Polymarket Whales.
Insight Prediction is a prediction market available outside of both the United States and Russia. Prices used are the “latest yes price.”
PredictIt is an experimental research and educational facility of Victoria University of Wellington in New Zealand, operating under a no-action-letter from the Division of Market Oversight of the CFTC (until it was rescinded last August, and then again, in March.) End of day “Yes” prices were used.
Smarkets is a British online betting exchange that allows peer-to-peer wagers on sports and politics. Probabilities were taken directly from the platform.
Betfred and Bet365 are established British bookmakers. Political gambling is legal in England and the British love betting on American politics. Odds were captured from oddschecker.com and converted into implied probabilities.
Manifold Markets is “a play-money prediction market platform where you can bet on anything.” End of day “Yes” probabilities were used.