Prediction market arbitrage gaps hit 12 live opportunities across Robinhood, Kalshi, and Polymarket
StartupHub.ai identified 12 live arbitrage opportunities across prediction market venues as of August 2, 2026, up from seven the prior day. The discrepancies involve the same real-world events priced differently on Robinhood, Kalshi, and Polymarket. A separate Hackernoon analysis cautions that direct price comparisons are complicated by differing fees, quote structures, and contract terms across platforms, suggesting some apparent gaps may reflect data normalization problems rather than true mispricing.
Traders chasing these gaps face a hidden cost: the platforms define price differently. Kalshi builds fees into displayed quotes, Robinhood shows raw midpoint prices, and Polymarket uses a no-fee model with wider spreads. A 2-cent gap that looks like free money can flip to a loss once settlement mechanics and withdrawal fees land.
The risk is sharpest for automated strategies scraping raw prices without normalizing for contract structure. StartupHub.ai's count jumped from seven to 12 in one day, suggesting either widening inefficiency or its own detection model is miscounting apples-to-oranges comparisons. For now, the arbitrageurs who survive will be the ones who read the fine print on each venue's settlement rules before clicking buy.