Kalshi widens lead over Polymarket as duo crosses $150B combined lifetime volume
Polymarket and Kalshi have surpassed $150 billion in combined lifetime trading volume, the platforms announced in early May. Kalshi drove the milestone with a record $14.81 billion in April notional volume, up 13.3% from March's then-record $13.07 billion. The April surge is notable because it occurred without major sporting events typically driving activity — no March Madness, Super Bowl, or NFL playoffs — suggesting Kalshi is building sustained trading beyond event-driven spikes. Kalshi extended its dominance into early May with a record $4.13 billion weekly volume, up 8.5% week-over-week, giving it 72.1% of combined volume versus Polymarket's $1.60 billion. Polymarket declined 6.2% in that weekly period. The milestone comes as monthly growth cools from earlier streaks and as regulators scrutinize prediction market ETFs.
Kalshi's 72.1% share of combined weekly volume and record April without major sports events puts it on track to permanently relegate Polymarket to a secondary venue ahead of the 2026 midterms, when both platforms expect their biggest event-contract demand.