BoJ Rate Hike Odds Explained: How TONA OIS Becomes a ‘70% Priced In’
A headline like ‘markets price a 70% chance of a BoJ hike’ comes, at its core, from one simplified calculation: (meeting-dated TONA overnight index swap rate minus the current policy rate) divided by the assumed 25bp hike size — a binary approximation that professionals refine further. Here is how that swap market works, how to run the arithmetic yourself, why fully priced hikes barely move stocks, and where to check the numbers before each of the BoJ’s eight annual meetings.









