Treasury chief Steven Mnuchin made an unusual move over the weekend in an attempt to soothe rattled financial markets. But based on the stock market's open, it appears that Mnuchin's call to the CEO of the six largest US banks didn't help. In fact, one financial analyst tells CNN that the call—meant to reassure the banks that all was well—might have actually spooked markets even more. Whatever the reason, the Dow plunged more than 400 points in the first hour of trading, threatening to dip below 22,000. As of 10:20am, the Dow was down 332, or 1.5%, and the S&P 500 (1.5%) and Nasdaq (1.1%) were similarly in the red. (The market woes reportedly have President Trump wondering about firing the Fed chief.)