Are I Bonds or TIPS Better for a Typical Retail Investor?
Inflation protection sounds like a single idea, but the government offers two distinct ways to get it, and the practical differences between them matter more than the shared goal they’re built around.
The short answer
I bonds and TIPS both aim to preserve purchasing power against inflation, but they do it through different mechanics and come with different rules around purchase limits, tradability, and taxes. I bonds are generally simpler and more restricted, purchased in modest annual amounts and held directly with the government, while TIPS trade more like a conventional bond and can be bought in larger amounts through a brokerage. Neither is strictly “better” — the right one depends on how much is being invested and how much flexibility matters.
How each one adjusts for inflation
An I bond’s return combines a fixed rate that’s set when it’s purchased with an inflation-adjusted rate that changes periodically based on measured inflation, blended together into one composite rate. TIPS take a different approach: the bond’s principal value itself adjusts up (or down) with inflation, and interest is paid as a percentage of that adjusted principal, so the interest payment amount changes over time even though the stated rate doesn’t. Both mechanisms are trying to solve the same problem — keeping real returns from being eroded — but they produce different cash flow patterns along the way.
Purchase limits and access
I bonds are typically capped at a modest amount per person per year, which makes them more of a savings tool than a place to park a large portfolio. TIPS have no comparable purchase cap and can be bought in much larger quantities, whether directly at auction or on the secondary market, which makes them more practical for someone trying to inflation-protect a meaningful portion of a larger portfolio rather than a modest side allocation.
Tradability
I bonds generally can’t be sold to another investor — they’re redeemed directly with the government, and only after an initial holding period, with an early-redemption interest penalty if cashed in within the first few years. TIPS, by contrast, trade on the secondary market like other treasuries, meaning they can be bought or sold before maturity at whatever price the market is offering at the time, for better or worse depending on where rates have moved.
Tax treatment differences
The two are also taxed somewhat differently in practice. I bond interest is generally not taxed until the bond is redeemed or reaches final maturity, which defers the tax bill to a single future point. TIPS, because their principal adjusts upward with inflation each year, can generate taxable income from that inflation adjustment even in years when no cash interest payment is actually received — a quirk sometimes called “phantom income” that’s worth understanding before buying TIPS in a taxable account rather than a tax-advantaged one. Tax rules in this area change over time and depend on individual circumstances, so it’s worth confirming current treatment before relying on any specific assumption.
Where each tends to fit
I bonds tend to suit smaller, steady savings goals — an emergency-adjacent cushion that keeps pace with inflation without much ongoing management. TIPS tend to suit larger allocations inside a diversified portfolio, particularly when held inside a brokerage account alongside other investments, where their tradability and lack of purchase limits are actual advantages rather than complications.
What to weigh
The practical decision often isn’t “I bonds or TIPS” in isolation but how much money is involved and how much flexibility is needed. A modest, steady saver may never bump into an I bond’s purchase limit and may prefer its simplicity, while someone allocating a larger sum toward inflation protection is more likely to need what TIPS offer in scale and tradability.