US Stocks Open Higher, Moderna Drops 7.1%

US stock markets opened with gains as the Dow Jones rose 0.2%, the S&P 500 climbed 0.3%, and the Nasdaq increased 0.4%. Moderna shares fell 7.1% following a downgrade from Citi from "neutral" to "sell." Robinhood rose 5.4% after launching 24-hour weekend stock trading, while Boeing gained 2.3% after securing a US Navy contract for next-generation fighter jets.