What's the difference between real yield and nominal yield, and why does real yield go negative?

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AcadiFi · Accepted Answer

**Nominal yield** is the stated yield on a bond in money terms. **Real yield** is the yield net of inflation — what you earn in purchasing power.

**Relationship (Fisher equation):**
(1 + Nominal) = (1 + Real) × (1 + Expected Inflation)

Approximation: Nominal ≈ Real + Expected Inflation

**How real yield is observed:**
- TIPS trade at a real yield directly
- For nominal bonds, subtract expected inflation from nominal yield
- Ex-ante real yield uses expected inflation; ex-post uses realized

**Why real yields go negative:**
A negative real yield means investors pay — in purchasing power — for holding the bond. This seems irrational but occurs when:

1. **Central bank quantitative easing:** Massive Treasury/TIPS purchases depress yields below natural levels (Fed's balance sheet hit $8.9T during COVID era).
2. **Flight to safety:** During crisis, investors hold TIPS despite negative yields for inflation protection and safe-haven status.
3. **Regulatory capital requirements:** Banks and insurers must hold high-quality sovereign debt regardless of yield.
4. **Inflation uncertainty > yield demand:** Investors prioritize protection from tail inflation over real return.
5. **Limited alternatives:** Pension funds and central banks have mandates requiring Treasury holdings.

**Example — 10Y TIPS real yield through the COVID era:**
- Pre-COVID (Jan 2020): +0.05%
- Peak stress (Aug 2020): −1.00% (investors paying 1% real/yr for protection)
- Post-hike cycle (Oct 2023): +2.40%
- April 2026: +1.80%

**Analyst use:**
- Real yields drive risk asset valuations (discount rate in DCF)
- Falling real yields typically lift equities and gold
- Rising real yields pressure long-duration assets and growth stocks
- Real yield = 'cost of capital' for the economy in purchasing-power terms

**Caveat:** Negative real yields compound over time — a 10-year bond at −1.0% real yield loses 9.6% of purchasing power if held to maturity.

What's the difference between real yield and nominal yield, and why does real yield go negative?

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