The $40 billion valuation exchange, @kalshi, half of its volume is just them playing both sides—left hand trading with the right hand. To see if an exchange is honest, don’t look at trading volume, look at the ratio of trading volume to open interest. Kalshi’s ETH perpetuals are at 60x. Binance’s BTC and ETH perpetuals have this ratio at 1-2x, Hyperliquid is at 0.5x. The drama started because Kalshi’s Crypto market manager, IcoBeast, posted a chart the other day asking, 'Guys, is 96.7% considered high?' and added, 'We charge trading fees, who would bother with wash trading?' This comment triggered Beni, a quant who specializes in spotting market inefficiencies. He immediately posted Kalshi’s perpetual rebate table, showing that takers pay 0.3 basis points, while makers earn a net 0.3 basis points. If two members trade $1 million nominal value back and forth, the platform earns nothing. Damn, their own rebate table literally says wash trading is free. Beni then followed up with screenshots of ETH perpetuals: $538.6 million traded in 24 hours, but only $3.1 million in open interest—a 174x ratio. All the trades were uniform, $5,500 per contract. Beni’s friend Octopus pulled all 4.1 million trades from September 5th to 18th and ran the numbers: $11.486 billion nominal value. On the ETH side, the $5,500 contract accounted for 59% of the volume, while on BTC, the $5,000 and $2,500 contracts combined for 57%. IcoBeast later clarified that the chart he posted was about prediction market share, while Beni was talking about perpetuals. Too late—the screenshots had already gone viral.