THE BLOCK: Tether and its USDT stablecoin "have become central to Iran’s shadow banking system," the top Democrat on the Senate Permanent Subcommittee on Investigations, Richard Blumenthal, said in a report released on Monday. "The Trump Administration’s glaring lack of oversight of cryptocurrency issuers has undermined our own national security interests," Blumenthal said. "That is why I am calling on the Department of Treasury and Justice to immediately investigate Tether and hold it accountable for these potential sanctions violations." On Monday, Tether said it is committed to blocking illicit finance, and said it had frozen hundreds of millions of dollars over the past year in wallets connected to Iranian entities.