Tether currently uses Cantor’s custody business to hold the billions of dollars of US Treasuries that support the value of its dominant USDT stablecoin. That custody relationship earns Cantor tens of millions of dollars a year, according to people familiar with the matter.Tether currently uses Cantor’s custody business to hold the billions of dollars of US Treasuries that support the value of its dominant USDT stablecoin. That custody relationship earns Cantor tens of millions of dollars a year, according to people familiar with the matter.