• Mark Hancock is a self- employed attorney who operates his law practice as an unincorporated sole proprietorship. In 2010, the IRS disallowed several business deductions he took in 2007 and 2008. In addition to 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?
• A partial list of research sources is:

Sec. 162, Sec. 163

Reg. Sec. 1.163-9T

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