TIPS Inflation Adjustments Can Raise Social Security Taxes Before Payout
A retiree holding TIPS in a taxable brokerage account owes tax each year on the inflation-driven increase in principal, even though Treasury does not pay that added principal until maturity. A $20,000 principal adjustment could lift provisional income from $40,000 to $60,000, making 85% of Social Security benefits taxable without any extra cash received. Putting TIPS in a traditional or Roth IRA avoids this annual phantom-income tax issue.
TIPS coupons are fixed, but Treasury adjusts principal with inflation and pays semiannual interest on that changed amount. At maturity, investors receive the larger of adjusted or original principal. In taxable accounts, the yearly principal increase is taxed as original issue discount even though the extra principal remains unpaid until maturity.
For a single retiree, Social Security taxation begins when provisional income exceeds $25,000 and can reach 85% above $34,000. These thresholds are not inflation-indexed. A $20,000 TIPS principal adjustment can therefore increase taxable benefits sharply without providing cash to cover the tax.
Retirees who hold TIPS in taxable accounts while receiving Social Security could face tax liabilities on inflation adjustments they have not yet received in cash. That may force some to sell other assets or reduce spending to cover the bill. It could also make tax-aware asset location more important, prompting advisers and savers to consider traditional or Roth IRAs for TIPS. The effect may be most acute for single filers near provisional-income thresholds, where small paper gains can sharply increase taxable benefits.