Original sentence: Buy-to-let mortgage is a mortgage arrangement in which an investor borrows money to purchase property in the private rented sector in order to let it out to tenants.For an owner-occupied property, the calculation is typically a multiple of the owner's annual income.Lenders calculate how much they are willing to lend using a different formula than for an owner-occupied property.Rental income is considered in the same way as salary, therefore tax is generally assessed at 22% or 40%.The interest rates and fees that are offered on BTL mortgages are, on average, slightly higher than those for an owner-occupied mortgage.These income tax incentives have made BTL investments more popular over the last few years
Edited sentence: Lenders use a different formula to calculate how much to lend than they do with an owner-occupied property, where a multiple of annual earnings is typically used.Rental income is considered in the same way as salary, and is therefore often taxed at 22% or even 40%.They are specifically designed for investors to borrow money to purchase property in the private rented sector in order to let it out to tenants.This tax set-up has made BTL investments more popular over the last few years.Typically the interest rates that are offered on BTL mortgages are fairly close to residential mortgage rates but will on average be higher and typically charge higher fees