Historically, Trump's announcements of trade agreements have led to increased market confidence and a boost in stock prices, particularly in industries that benefit from international trade. The agreement with the UK, a key ally and trading partner, may have a positive impact on the stock market, especially for companies involved in transatlantic trade. The announcement may also lead to increased investment in the US and UK, as companies take advantage of the newly cemented relationship. However, the impact may be limited by the lack of specific details on the agreement, and the market may wait for further clarification before making significant moves. Overall, the announcement is likely to contribute to a positive market sentiment, with a potential increase in stock prices for companies that stand to benefit from the agreement.