Banks can now issue stablecoins post-GENIUS, raising competition against Tether and Circle’s $245B supply share. The stablecoin market, long dominated by Tether and Circle, is starting to fracture. The supply share of the so-called “big two” has slipped after peaking last year, suggesting that the age of a pure duopoly may be ending. The Tether and Circle Grip on Supply SlipsAccording to Carter, Tether and Circle together command about 86 percent of all stablecoin supply. Carter concluded that while Tether and Circle remain dominant, the duopoly is no longer secure.