An existing single tenant building measures 45,000 SF. It has a tenant paying an in place rent of $100/SF/Yr and operating expenses are $40/SF/Yr. The prevailing cap rate for this property is 4.5%. The building is for sale. Assume during due diligence that the buyer discovered that the roof needs to replaced at a cost of $2.5M. Assume that the seller agrees to an adjustment in price equal to the cost to replace the roof. What is the sellers effective cap rate after agreeing to give a credit for the roof work?