Who sells parlays, and how long are they?

Volume-weighted over each venue’s own window, shown beside the bar; the tick is its last days.

Kalshi’s share is of its whole book, not just sport — every other venue here is a sportsbook.

OG/Crypto.com, Underdog and Polymarket US publish no leg breakdown — absent here, not zero. DKeX publishes none either, but its settlement report names every leg, so the count is recovered rather than reported.