Presidential election markets are the largest markets on prediction market platforms. For example, Kalshi’s presidential election market had over $400 million in trading volume the morning after the election. The platform’s popular vote market only had $46 million at the same time.
PredictIt’s number of contracts saw the most growth. Their number of contracts went from about 350,000 on Nov. 4 to 1.5 million on Nov. 5. The day after Election Day saw 2 million contracts traded.
On other platforms, the already high trading volume limits the number of times that presidential election markets double on Election Night.
Kalshi doubled its trading volume from the day before Election Day. Kalshi’s presidential winner market went from $200 million on Nov. 4 to $400 million on the morning of Nov. 6. However, Kalshi only launched its election markets at the beginning of October.
From Election Day to the morning after, volume in Polymarket’s presidential winner market only grew by about 14%. However, that growth was from $3.2 billion to $3.6 billion.
The presidential election markets show the limits of how fast a prediction market can grow.
Inverse relationship between size and growth
Trading volume in the presidential markets started large and grew modestly compared to smaller events.
For example, Polymarket’s Vice Presidential Debate trade volume increased from about $225,000 to almost $822,000 from the morning of the debate to the minutes after. Trade volume doubled again on the Monday after to $1.7 million. Traders were waiting for the polls that would settle the market and kept trading well after the debate’s end.
But trading volume was much smaller in the VP debate market than the presidential election market. The VP market had room to grow that the presidential election market lacked.
This will be important data for the 2028 presidential election. Prediction markets will have grown a great deal by then and will demonstrate growth more comparable to PredictIt’s mature rate of growth in 2020 compared to the rapid startup growth that Kalshi enjoyed throughout October.
