Updates and corrections
Platforms, fees and laws change faster than books get reprinted. Every change since the book went to print is logged here, newest first.
Checked October 20, 2026Log
- First edition. Every fee, rule and legal status in the book and on this site was checked on this date.
- Polymarket US changed its fee to 0.0695 × contracts × P × (1 − P), rounded to the nearest cent on each fill. The book and the calculators use the new rate.
Dates to watch
- Kalshi’s response is due on the Supreme Court petition in Flaherty v. KalshiEX.
- Comments close on the CFTC proposal to add event contracts to the definition of a swap.
- Fourth Circuit (Maryland) ruling on Kalshi’s sports contracts; Second Circuit (New York) in briefing.
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