Looking at the average trading volume over the past 7 days, the prediction market landscape seems to be entering an era of four-way dominance. The Top 4 markets—Kalshi, Polymarket, Opinion, and Probable—each hold over 20% of the trading volume market share. However, in terms of open interest, the disparity is particularly striking: Polymarket and Kalshi exceed $300 million, Opinion is close to $150 million, while Probable is only around $4 million.