Prediction markets went from $15.8 billion in 2024 to $63.5 billion in 2025. Most of that volume sits on three platforms: Kalshi, Polymarket, and Opinion. Hyperliquid is about to enter the space. HIP-4 ships in weeks, and it puts perps and prediction markets in one account. The part that caught my attention is the capital efficiency angle. Your perp position and your prediction market position sit in the same collateral pool, so when one moves against you, the other offsets it. Same starting stack but w/ way more capital efficiency. The fee structure is worth looking at too: • Opening a position is free. You only pay when you close or settle (7 bps taker, 4 bps maker) • 1x isolated margin, no liquidation, max loss is what you paid in • Flip YES to NO in a single action. No slippage, no double fees • Burn a YES+NO pair to get your collateral back instantly To put that in perspective, Polymarket charges ~2% on winnings. Kalshi takes ~7%. Hyperliquid: 4 to 7 bps (0.04% to 0.07%). If you're actively trading prediction markets, that gap adds up fast. That said, market share doesn't flip on fees alone. Polymarket and Kalshi own 92% of prediction market volume between them. They're both well funded, and Polymarket has a loyal base of POLY airdrop farmers waiting on the TGE. The thing I'm watching is whether the cross-margin angle is enough to pull active traders off the incumbents. Volume and market share over the next few months will tell the story. Shoutout to @Yaugourt who wrote the most comprehensive technical breakdown of HIP-4 I've seen. A lot of the details here come from his research and @androolloyd's work decoding the system from the hl-node binary.(Edgy - The DeFi Edge 🗡️)