Jefferies puts October prediction-market daily volume at record $4.13 billion

Average daily trading volume across the yes-or-no prediction-market exchanges tracked by Jefferies climbed 55% in October to a record $4.13 billion. Open interest rose 45% from September to $3.27 billion, also a record.

The analyst Daniel Fannon attributed part of the acceleration to the college-football and NFL seasons. Sports contracts generated average daily volume of about $2.98 billion, up 55% from September, and represented 78% of total daily volume, unchanged from the previous month.

Sports accounted for an even larger share of outstanding positions. Its share of total open interest rose to 83% in October from 73% in September. Fannon said weekend growth in combination contracts, or parlays, was consistent with their use for NFL and college-football activity; DraftKings’ DKeX benefited from that pattern.

The start of the 2026-27 NBA season also helped lift sports trading. Non-sports contracts rose at the same 55% monthly rate, reaching average daily volume of $843 million.

Polymarket recorded $655 million in October average daily volume, a 50% monthly increase and 395% gain from a year earlier. Its 17% share of the platforms Jefferies tracked was unchanged from September. Other tracked platforms reported $309 million in daily volume, up 56% month on month and 710% year on year, while retaining roughly a 7% share.

Rothera, the all-or-nothing exchange launched in June by Robinhood Markets and Susquehanna International Group, recorded average daily volume of $49 million. That was 55% higher than September, although its share of industry daily volume fell to 1.2% from 1.5%.

The figures provide an average-daily measure of the October trading surge documented in our Oct. 21 coverage of monthly volumes at individual platforms. They also extend a sports-led pattern identified by Pew Research Center: combined monthly global volume on Kalshi and Polymarket rose from $26 billion in May to $53 billion in July, largely because of sports activity. Pew measures volume as notional taker volume, counting each contract at its $1 face value rather than the price at which it traded.

The rapid expansion has also prompted questions about the quality of some reported activity. CNBC reported in September that outside observers had flagged unusual trading patterns on Kalshi and Polymarket and raised the possibility of wash trading, allegations both companies denied. A Columbia University study cited by CNBC found its indicators of such activity had fallen to negligible levels by April.