The FTSE 100 fell on Monday, after two sessions of gains, as a new UK-US trade deal took effect. The agreement reduces tariffs on British car exports from 27.5% to 10% and eliminates duties on aerospace goods like engines and aircraft parts. However, a baseline 10% car tariff remains, and a deal on zero tariffs for core steel products is still pending. Meanwhile, the UK’s Q1 GDP growth was confirmed at 0.7%. Still, mortgage rates have steadily moved lower this year and data showed mortgage approvals rising more than expected. Among single stocks, AstraZeneca fell around 1%, oil majors Shell and BP were down 0.8% and 1%. Homebuilders were among the worst performers, with Persimmon, Barratt Redrow and Taylor Wimpey down by 3-4%. Also, Centrica dropped 1.5% after a JPMorgan downgrade. On the other hand, Rolls-Royce rose over 1.5%, BAE Systems was up nearly 1.3%, and gold miners Fresnillo and Endeavour gained more than 0.4%.