500 SPX names mapped to 2,500 Kalshi references is a decent primitive, but most of the first book is still macro factor beta dressed up as single-name hedging: recession odds, rates, inflation, hurricanes, housing prints. The jump happens if Kalshi can put these event legs and its newly CFTC-approved BTC perp under one collateral/margin regime, because then MM desks can arb event probability against SPX options, sector ETFs, and crypto perps. Until depth shows up, Hedgebook is better as a factor-discovery UI than a CFO-grade hedge, but that is how Polymarket-style toys become serious venue flow.

Top comment by @Benthic