Although the GOP tax overhaul will dampen use of the once-sacred mortgage interest deduction by consumers, owners of mortgage companies will be able to keep more of the money they earn each year, according to interviews conducted by Inside Mortgage Trends. In particular, firms that have C-corporation status will benefit the most, thanks to a reduction in the corporate tax rate to 21 percent from 35 percent. S-corps, on the other hand, likely will not do as well because ...