Central banks beyond the Fed

The closest central bank call on the board is the ECB on October 29, and it is close to the decimal. Kalshi prices maintain at 51% against hike 1–25bps at 48%; Polymarket, on $12,084, has no change at 49% against a 25bp increase at 50%. Two venues, no shared order book, one point apart on a genuine coin flip.

The Bank of Japan, deciding the same week, is not close. Kalshi has hold at 77% and Polymarket at 82%—but the busiest contract on the Kalshi board is hike more than 25bps at 3%, on $1,258, ahead of the 77% consensus leg at $867. Polymarket's second-busiest leg is its own 2.9% tail.

And December already has a view. Polymarket's December ECB board puts a 25bp increase at 60% and no change at 28%, which is a stronger statement about the path than anything the October board is willing to make about the meeting itself.

Kalshi and Polymarket both list the October 29 decision. Hold is 77% on one and 82% on the other; every hike leg is priced under twenty cents on both.

Left: maintain current rate at 77%, the consensus, on $867 and 1,310 contracts.

Right: hike more than 25bps at 3%, on $1,258 and 1,659 contracts—more money and more open interest than the outcome the board expects. A fifty-basis-point surprise from a bank that has moved once this cycle is the cheapest lottery ticket on this page, and it is the one being bought.

Kalshi: maintain 51%, hike 1–25bps 48%, on 3,699 and 3,103 contracts standing. Polymarket: no change 49%, 25bp increase 50%, on $3,610 and $3,476.

Four quotes, two venues, and nothing more than two points from an even split. This is the only major central bank decision on the board without a favourite.

The same two banks, one meeting further out. December's ECB board has a 25bp increase at 60% against no change at 28%—so the October coin flip resolves into a hiking bias by year end.

South Africa decides on September 23, five days from now, and it is the most interesting board here. Hike 1–25bps leads at 63% on $2,111—but maintain current rate, priced at 8%, has taken $2,427 and carries 4,037 contracts, more than the favourite on both counts. A board whose consensus leg is being outtraded four-to-one by an eight-cent alternative is a board where somebody disagrees with the consensus and is willing to pay for it.

Russia on October 23 is a three-way: hold 58%, cut 1–25bps 29%, cut more than 25bps 10%. Canada on October 28 splits maintain 65% against hike 25bps 38%, on roughly 25,000 contracts a side and $1,717 of daily flow.

South Africa decides September 23, Russia October 23, Canada October 28, and the ECB and the Bank of Japan both on October 29.

• The ECB at 51/48 and 49/50. Six weeks is a long time for a coin flip to survive. Whichever way it breaks, the two venues breaking together is the thing to check.
• South Africa's 8% hold leg outtrading the 63% favourite. Five days out, that is either information or a very confident hedge.
• The Bank of Japan's 3% tail carrying more money than its 77% consensus. The same pattern as the crypto and soccer books in this catalog, on a page where it has no obvious retail explanation.
• December's ECB at 60% for a hike, against an October board that will not commit. The path is priced with more conviction than the next meeting.
• Canada's legs sum to 103%. Thin two-sided quotes on 52,000 contracts of standing interest; the arithmetic is a liquidity artefact, not an arbitrage.