Mark Hancock is a self-employed attorney who operates his law practice as an unincorporated sole proprietorship. In 2018, the IRS disallowed several business deductions he cook in 2016 and 2017. In addition co paying the deficiency and assessed penalties, he also pays $18,000 in interest on the tax owed. Can he deduct that interest in the current year?

• Sec. 162, Sec. 163

• Reg. Sec. 1.163-9T

• Kikalos v. Comm., 84 AFTR 2d 99-5933