The qualified business income (QBI) deduction is not a business deduction; it does not appear on Schedule C or any other business tax return. Instead, it is a personal deduction on Form 1040 that is subtracted after reducing adjusted gross income by the standard deduction or itemized deductions.
The difference between face value of a bond and lower market price, attributable to rising interest rates. On a sale, gain on the bond is generally taxed as ordinary income to the extent of the discount.