ALT Line and scatter plot titled 'Market Maker Edge for Select Uncorrelated Combos Relative to Pre-Fees Mean.' The y-axis shows edge change versus the pre-fee mean, in cents per contract; the x-axis spans August 18–22, 2026. Grey dots are hourly averages of market-maker edge on Kalshi combos priced between 20 and 80 cents, combining our fills with competitors' fills. A bold purple line is the fill-weighted 24-hour rolling average with a ±1 standard error band; a solid grey line marks zero (pre-fee baseline), a dashed vertical line marks the August 20 fee launch at 03:59 UTC, and an annotation marks the post mean of +0.42 cents. Before fees, the rolling line hovers near zero with slight upward drift. After fees go live, it climbs steeply for 12–18 hours, then holds flat near +0.4 cents: competitors moved prices about 0.4 cents further from our fair value once maker fees took effect.