Both I-Bonds and TIPS protect against inflation. But they work completely differently — and one is clearly better depending on your situation.
I was surprised by some of these findings when I first dug into the research.
How Each Works
I-Bonds: Purchased directly from TreasuryDirect.gov. Rate = fixed rate + inflation rate (CPI-U), adjusted every 6 months. Cannot sell for 12 months; 3-month interest penalty if sold before 5 years.
TIPS: Treasury Inflation-Protected Securities. Traded on the open market (or via ETFs like TIP, VTIP). Principal adjusts with CPI. Pay semi-annual coupon on the adjusted principal.
Head-to-Head Comparison
| Factor | I-Bonds | TIPS |
|---|---|---|
| Purchase limit | $10,000/year per person | Unlimited |
| Liquidity | 1-year lockup, 5-year penalty | Sell anytime on market |
| Tax treatment | State tax exempt; federal deferred | State tax exempt; phantom tax issue |
| Deflation protection | Never goes below purchase price | Par value guaranteed at maturity only |
| 2026 rate (approx) | 3.1% composite | Real yield ~2.0% |
| Best for | Emergency fund, small savers | Large portfolios, retirees |
The TIPS “Phantom Tax” Problem
TIPS adjust your principal upward with inflation — but the IRS taxes that adjustment as income, even though you haven’t received it. This creates a tax bill on money you haven’t actually received. Solution: hold TIPS in tax-advantaged accounts (IRA, 401k).
My take: the research points in a clear direction here.
Does this match your experience?
The Decision Framework
- Under $10K to invest: I-Bonds (guaranteed, no market risk)
- Over $10K and need liquidity: TIPS ETF (VTIP for short-term, TIP for broad)
- Emergency fund replacement: I-Bonds (after 12 months, better than savings accounts)
- Retirement portfolio allocation: TIPS in IRA (avoids phantom tax)
- Maximum protection: Both — $10K in I-Bonds + TIPS for the rest
Investment disclaimer: This is educational content. Consult a financial advisor for personalized advice.
