The Summer Budget hit the buy-to-let investor in more than one way. Investors often finance the acquisition of an investment property with a commercial loan. The annual interest paid on the loan is deducted, together with other qualifying expenses, in calculating the taxable rental profits for the year. A top rate taxpayer would therefore receive 45% tax relief on his interest costs. By April 2020, only basic rate tax relief will be given at 20%. Between now and then, the reduction in relief will be phased in.