Are Election Betting Markets Manipulated?

Summary

Short answer ... no

The betting markets are taking their lead from the simple average such as the one calculated by Real Clear Politics.

In other words, betting markets follow an identifiable rationale and are not diverging into a random pattern that would be associated with manipulation.

The bottom line is that everything below has Trump’s odds improving.

The betting markets and the simple average poll aggregation show Trump’s odds as improving and ahead. Nate Silver's Silver Bulletin models suggest Trump is improving and narrowing Harris’s lead.

And all of it is well within the “too close to call” range.

Presidential Betting Markets

We are fans of election betting markets. They aggregate all known information into one probability. Manipulating them is pointless. It will not change anyone’s vote. Even if bettors are partisan, they are there to make money, not express support for a particular candidate.

They are no more predictive than polls, but they are real-time, so they can measure how much things have changed faster than polls in the wake of important events.

Real Clear Politics averages the eight largest betting markets in terms of the probabilities of who will win.

Recently, Trump (orange) has jumped ahead of Harris (blue), 54% to 45%. Despite this jump, this race is still best termed “too close to call.” Only once these markets widen to more than 66% to 33% can we say someone has a meaningful lead.

How consistent are these markets??

The following chart shows Trump’s betting.?It includes the same average of all betting markets shown above (black) and the two largest betting markets,?Polymarket (blue) and Predictit (orange).

Effectively, they all have the same results and trends.

Similarly, Harris’s betting is below.?The average of all markets is?black,?Polymarket?is blue, and?Predictit is?orange.

While Predicitit is somewhat diverging from the rest, they still effectively give the same results and trends.

Are All Betting Markets Manipulated?

Above, we show the consistency of betting markets. But are they all being manipulated?? To answer this, let’s look at the largest market, Polymarket.

Polymarket has markets for all 50 states. The charts below detail how betting unfolds.

Let’s start with the current map. If Trump leads in a state by more than 66%, it is red. States in which Harris leads by more than 66% are shaded blue, and any state between 33% and 66% is gray.

The seven swing states most think will determine the election are gray. The latest probability that the Democrat (Harris) will win is shown.

The following chart converts the map above into implied electoral college votes. Trump (orange) has jumped to a 302 to 236lead (270 needed to win).

How did this implied electoral college vote lead happen? The following chart shows the probability that the Democrat (Harris) will win.

Pennsylvania (brown), Michigan (red), and Wisconsin (purple) all fell below 50%, meaning these states switched to Trump (above 50%).

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Comparing Bettors to the Polls

One of the more popular?Poll-Aggregating sites is?Real Clear Politics. They?aggregate all the state polls into a simple moving average.

Below is the latest map from these averages. This is the “no toss-up” map, meaning they assign the leader even if they lead polling average by just 0.1%.

This map shows the same lead as the aggregated Polymarket map above. Below is the recent trend of implied electors from the Real Clear Politics no-toss-up map.

In the next chart, we overlay Trump’s implied electors for Polymarket (orange), Real Clear Politics (red), and Nate Silver’s Silver Bulletin election model (green).

And the following chart overlays Harris’s implied electors for Real Clear Politics (red), Polymarket (blue), and Silver Bulletin (green).

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Note that Polymarket (blue) and Real Clear Politics (red) closely track each other. So, it appears that the betting markets are taking their lead from the simple average such as the one calculated by Real Clear Politics. In other words, betting markets follow an identifiable rationale and are not diverging into a random pattern that would be associated with manipulation.

Silver Bulletin

The green line in the chart above, the implied electoral college votes from Nate Silver’s Election Model, diverges from the Real Clear Politics simple moving average. His model incorporates many more variables, such as weighting pollsters based on their track record, economic indicators, money raised, etc.

The next chart shows the implied electors from this model. Harris (blue) leads Trump (orange) 277 to 261.

And his overall model has Harris leading 52% to 48%.

There are two things to note about his model. First, it is a probability of winning. So, like the betting markets, anything between 66% and 33% is best termed “too close to call.”?

Second, Harris (blue) has trended lower over the last few weeks, Trump (orange) has trended higher, and Harris’s lead has narrowed.

The bottom line is that everything above has Trump’s odds improving.

The betting markets and the simple average poll aggregation show that Trump’s odds are improving. Silver Bulletin suggests Trump is improving and narrowing Harris’s lead.?

And all of it is well within the “too close to call” range.