Inflation-Linked Bonds: Protect Your Portfolio from Rising Prices

Key Concepts

• Conventional Gilt: A standard UK government bond with fixed coupon and redemption payments.
• Index-Linked Gilt (Linker): A bond where payments are adjusted based on inflation to protect purchasing power.
• RPI (Retail Prices Index): The inflation measure used to adjust linker payments.
• Index Ratio: The multiplier (Current RPI / Base RPI) applied to payments to account for inflation.
• Break-even Inflation: The rate at which a linker provides the same return as a conventional gilt.
• Dirty Price: The actual purchase price of a bond, including accrued interest and the inflation-adjusted uplift.
• Real Yield: The annualized total return expected after accounting for inflation.

1. Mechanics of Index-Linked Gilts

The core function of a linker is to protect the investor's purchasing power rather than providing a fixed cash amount.

• The Index Ratio: Every payment (coupon or redemption) is multiplied by the Index Ratio. If a bond was issued at an RPI of 164 and the current RPI is 406, the ratio is 2.47, meaning payments are 2.47 times larger than the nominal coupon rate.
• Inflation Lag: To ensure market certainty, there is a built-in lag for the RPI figure used:
  • Post-2005 issues: 3-month lag.
  • Older issues: 8-month lag.
• Coupon Structure: Linker coupons are intentionally low (often <1%) because they represent the "real rate" above inflation, not the total return.

2. Four Common Misunderstandings

The speaker identifies and clarifies four frequent points of confusion:

1. Break-even Inflation: It is not a "loss threshold." If inflation is lower than the break-even rate, the investor hasn't lost money; they have simply earned less than they would have with a nominal gilt. It represents an opportunity cost.
2. Redemption Value: Unlike nominal gilts that return £100 at maturity, linkers return £100 multiplied by the Index Ratio. This means the capital value grows with inflation, often resulting in a much larger final payment than the initial nominal investment.
3. Dirty Price: Investors often see a "clean price" (e.g., £103) and are shocked by a "dirty price" (e.g., £177). The difference is not a hidden fee but the accumulated inflation since the bond's issuance.
4. Real Yield as Income: The real yield is an annualized total return metric, not an income figure. Because coupons are tiny, the vast majority of the return is "backloaded" into the final inflation-adjusted redemption payment.

3. Practical Application and Strategy

• Taxation: In the UK, gilts are exempt from Capital Gains Tax (CGT). Since a large portion of a linker's return comes from the inflation-adjusted capital uplift at maturity, this tax exemption is highly valuable.
• Negative Real Yields: Short-dated linkers sometimes show negative real yields. This indicates that investors are paying a premium for the certainty of near-term inflation protection, effectively accepting a lower return for the safety of the asset.
• The 2030 Shift: From February 2030, the RPI index will be aligned with CPIH, which typically runs 0.8% to 1% lower. This will reduce the inflation uplift for long-dated linkers maturing after 2030.

4. Decision Framework: Nominal vs. Linkers

• Use Conventional Gilts if: You have a specific, fixed-cash liability (e.g., paying off a mortgage on a specific date).
• Use Linkers if: You are planning for retirement and need to maintain a standard of living that fluctuates with the cost of goods and services.

5. Notable Quotes

• "You don't know the exact cash amount of each payment in advance... but you do know what that money will buy. Your spending power is protected."
• "Fewer units doesn't mean less money. The index ratio does the heavy lifting."

Synthesis

Index-linked gilts are specialized tools designed to hedge against unexpected inflation. While they are often misunderstood due to their complex pricing (Index Ratio and Dirty Price), they are superior to nominal gilts for long-term wealth preservation. Investors must account for the "backloaded" nature of returns, the impact of the 2030 index methodology change, and the fact that the real yield is a total return metric rather than a simple income stream.