新浪财经隔夜要闻大事汇总：2026年2月28日

Market - US stock market closed down with the Dow Jones falling over 500 points, and all three major indices recorded weekly declines. The Dow, Nasdaq, and S&P 500 dropped by 1.05%, 0.92%, and 0.43% respectively [2] - UBS downgraded the US stock market rating due to concerns over a weakening dollar, high valuations, and rising policy risks [2] - The Producer Price Index (PPI) for January rose more than expected, with core PPI increasing by 0.8% month-on-month, indicating persistent inflation [2] Company - Dell's stock surged by 21.93% after strong revenue forecasts, while Nvidia's stock fell by 4.16% despite exceeding earnings expectations due to concerns over the sustainability of AI spending [3] - Paramount has reached a final merger agreement to acquire Warner Bros. Discovery, valuing the company at $110 billion, with the deal expected to close in Q3 2026 [33] - Trump Media is considering spinning off its social platform Truth Social into an independent company, marking a significant shift for the firm [31] - TPG disclosed a £44 million exposure to the troubled UK lender Market Financial Solutions (MFS), indicating a small percentage of its overall loan exposure [37] Macro - US companies disclosed stock buyback plans totaling $233 billion in February, marking the highest level for the month in history [12] - The SEC announced new regulations requiring foreign company executives to disclose stock trades promptly, aligning with US standards [14] - The US government is facing over 2,000 lawsuits for tariff refunds following a Supreme Court ruling declaring many tariffs unconstitutional [17]