# Prediction Market Arbitrage: 5 Opportunities Live Now on Polymarket, Kalshi, and PredictIt (July 27, 2026) _Our cross-venue engine has identified five live prediction market arbitrage opportunities, allowing users to lock in guaranteed profits by buying YES on one venue and NO on another for under $1._ **Published:** 2026-07-27 **Source:** https://www.startuphub.ai/ai-news/prediction-markets/2026/prediction-market-arbitrage-5-opportunities-live-now-on-polymarket-kalshi-and-predictit-july-27-2026 --- For those new to the concept, an arbitrage lock in prediction markets occurs when you can buy a 'YES' contract on one platform and a 'NO' contract for the same event on another platform, with the combined cost being less than $1. This strategy guarantees a profit regardless of the event's outcome, as one of your contracts will always pay out $1. As of July 27, 2026, our StartupHub.ai engine has surfaced five such opportunities across Polymarket, Kalshi/Robinhood, and PredictIt. These spreads can close rapidly due to market dynamics, and potential profits should always be considered alongside platform fees, KYC requirements, and withdrawal limits. Arbitrage ROI by event. Will Alexandria Ocasio-Cort...: ROI % 25. Who will be the Prime Minis...: ROI % 21.95. Who will be the next Suprem...: ROI % 6.61. Who will win the 2028 US pr...: ROI % 3.9. Will Kamala Harris and Gavi...: ROI % 3.09. Cross-venue spreads on July 27, 2026. Source: StartupHub.ai arbitrage engine. **Live arbitrage right now** These update automatically. Tap a leg to open the venue. Not financial advice. - **Will Alexandria Ocasio-Cortez win the 2028 Democratic presidential nomination?**. Arbitrage: 25.0% ROI, locks 20c per $1. Buy YES on [PredictIt](https://www.predictit.org/markets/detail/8153/Who-will-win-the-2028-Democratic-presidential-nomination) at 14c, buy NO on [Kalshi / Robinhood](https://kalshi.com/markets/kxaocsenate) at 66c. - **Who will be the Prime Minister of Israel after the 2026 election?, Benjamin Netanyahu**. Arbitrage: 22.0% ROI, locks 18c per $1. Buy YES on [Kalshi / Robinhood](https://kalshi.com/markets/kxnextisraelpm) at 13c, buy NO on [PredictIt](https://www.predictit.org/markets/detail/8643/Who-will-be-the-Prime-Minister-of-Israel-after-the-2026-election) at 69c. - **Who will be the next Supreme Court justice? Will Emil Bove become the next Justice on the Supreme Court?**. Arbitrage: 6.6% ROI, locks 6c per $1. Buy YES on [Kalshi / Robinhood](https://kalshi.com/markets/kxscourt) at 5c, buy NO on [PredictIt](https://www.predictit.org/markets/detail/8246/Who-will-be-the-next-Supreme-Court-nominee) at 89c. - **Who will win the 2028 US presidential election?, Gavin Newsom**. Arbitrage: 3.9% ROI, locks 4c per $1. Buy YES on [Polymarket](https://polymarket.com/event/will-gavin-newsom-win-the-2028-us-presidential-election) at 12c, buy NO on [PredictIt](https://www.predictit.org/markets/detail/8171/Who-will-win-the-2028-US-presidential-election) at 84c. - **Will Kamala Harris and Gavin Newsom be the two frontrunners for the 2028 Democratic Presidential Nomination?**. Arbitrage: 3.1% ROI, locks 3c per $1. Buy YES on [Kalshi / Robinhood](https://kalshi.com/markets/kxpresnomd) at 18c, buy NO on [PredictIt](https://www.predictit.org/markets/detail/8153/Who-will-win-the-2028-Democratic-presidential-nomination) at 79c. [See the full live arbitrage board](https://www.startuphub.ai/arbitrage) or poll the free [JSON API](https://www.startuphub.ai/api/v1/arbitrage). ## Track these live, or poll the free API The board above refreshes on its own, so this page stays current long after today. The full cross-venue feed lives on the [arbitrage board](https://www.startuphub.ai/arbitrage), and every match is also a free JSON API and an MCP tool, so a trading agent can poll live Polymarket, Kalshi and PredictIt arbitrage opportunities and act on them. ``` curl https://www.startuphub.ai/api/v1/arbitrage?arbs_only=1 ``` [Read the arbitrage API reference](https://www.startuphub.ai/api-docs/reference/arbitrage) or open the [live JSON endpoint](https://www.startuphub.ai/api/v1/arbitrage). *Informational feed, not financial advice. Live arbitrages are often fleeting, and fees, gas, KYC and withdrawal limits eat into the spread. Verify each market’s resolution rules and costs before trading.* --- Original analysis from [startuphub.ai](https://www.startuphub.ai), the #1 AI startup directory. © StartupHub.ai. All rights reserved. You may not republish this article in full without a license. Search engines and AI research tools may crawl and summarize for reference. Bulk reproduction or model training on this content requires a license. See https://www.startuphub.ai/terms.