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Price-Yield Relationship

Credit Spread vs Rate Shift

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Credit Spread vs Rate Shift

Bond investors often lump all price losses together, but understanding whether losses came from rising Treasury rates or widening credit spreads is essential for portfolio management and future decisions. The two risks behave differently across economic cycles and require different hedging strategies.

Key takeaways​

  • Rate risk (Treasury yield changes) affects all bonds; spread risk (credit premium changes) affects only corporate bonds.
  • In recessions, spreads widen while rates might fall, creating a divergence in bond performance.
  • In expansions, spreads narrow and rates typically rise, sometimes offsetting each other.
  • Decomposing bond losses reveals whether to adjust rate timing or credit positioning.
  • A total-return loss of 5% could be −8% from rates and +3% from spread compression.

The Two-Source Model​

Every corporate bond return can be decomposed into:

Return = Coupon + (Treasury Duration Loss/Gain) + (Spread Change Loss/Gain)

Suppose you own a 5-year, 5% coupon investment-grade corporate bond at par (100), currently yielding 5.1% (100 bps above the 4.1% Treasury). Over the next year:

Scenario A: Rates rise, credit stable

  • Coupon received: +5%
  • Treasury yield rises to 5.1%, causing price loss on 4.8-year duration: −4.8%
  • Spread remains 100 bps: 0%
  • Total return: +5% − 4.8% + 0% = +0.2%

The duration math works: you expected to lose 4.8% from the rate rise, but the 5% coupon offset most of it.

Scenario B: Rates stable, spread widens

  • Coupon received: +5%
  • Treasury yield unchanged: 0%
  • Spread widens from 100 bps to 150 bps, causing price loss on 4.8-year duration: −2.4% (4.8 × 0.5%)
  • Total return: +5% + 0% − 2.4% = +2.6%

Even though rates didn't change, you lost money to spread widening. But the coupon income partially offset it.

Scenario C: Rates fall, spread widens (recession)

  • Coupon received: +5%
  • Treasury yield falls to 3.1%, causing price gain on 4.8-year duration: +4.8%
  • Spread widens from 100 bps to 250 bps, causing price loss on 4.8-year duration: −7.2% (4.8 × 1.5%)
  • Total return: +5% + 4.8% − 7.2% = +2.6%

This is a classic recession scenario: rates fall (benefiting bonds on a Treasury basis), but spreads widen dramatically (hurting corporate bonds). The net effect depends on the magnitudes.

Historical Example: 2008​

At the start of 2008, a typical investment-grade corporate bond might have had:

  • 5-year duration: 4.5 years
  • Spread: 120 bps above Treasury
  • Yield: ~4.5%

By October 2008:

  • 5-year Treasury yield: fell from 3.5% to 2.1% (−1.4%)
  • Spread: widened from 120 bps to 500+ bps (+380 bps)
  • New corporate yield: 2.1% + 5.0% = 7.1%

A buy-and-hold investor received the coupon (4.5%) but faced:

  • Rate gain from falling Treasury yields: +4.5 × 1.4% = +6.3%
  • Spread loss from widening: −4.5 × 3.8% = −17.1%
  • Total: +4.5% + 6.3% − 17.1% = −6.3% loss

The Treasury duration actually protected the portfolio (falling rates create capital gains), but the spread widening completely overwhelmed that benefit. A Treasury-only investor holding bonds with the same 4.5-year duration would have gained 6.3% from the falling 5-year Treasury yield.

This is why corporate bonds are considered "equity-like" in bad recessions: they have high correlation with stocks (both suffer when credit spreads widen and growth expectations collapse) despite their lower volatility in normal times.

Different Cycles, Different Dynamics​

Early-Stage Recovery​

After a recession, central banks are cutting rates aggressively (rates fall, helping all bonds), and credit stabilizes (spreads narrow, helping corporates especially).

Example: Mid-2008 to 2009. The Fed slashed rates from 5% to near zero. Spreads narrowed from recession highs. An investment-grade corporate bond investor captured:

  • Rate gains from falling Treasuries: +15% or more
  • Spread compression: +10% or more
  • Total: +25%+ returns despite economic pain

A Treasury investor got only the rate gain, missing the spread compression bonus.

Expansion (Mid-Cycle)​

Growth expectations are rising, central banks stop cutting and eventually raise rates (bad for bonds), but credit is strong (spreads stable or narrowing).

Example: 2013–2017. The Fed raised rates from near zero to 2.5%. Investment-grade corporate bond returns:

  • Rate loss from rising Treasuries: −2% to −3%
  • Spread compression from strong credit: +2% to +3%
  • Total: roughly flat to slightly positive, or slightly negative

Treasury investors lost outright. Corporate bond investors broke even or lost less because spread compression offset rate losses.

Late-Cycle / Recession Onset​

Growth is slowing, central banks start cutting (good for bonds), but corporate credit is weakening (spreads widen, bad for corporates).

Example: 2019. Fed cut rates three times, and long-term growth expectations moderated. Investment-grade corporate bonds:

  • Rate gain from falling long-term yields: +2% to +3%
  • Spread widening from growth fears: −1% to −2%
  • Total: +1% to +2% net gain

Corporate bonds outperformed because the rate benefit exceeded the spread widening. But in 2020 (deeper recession fears), spread widening accelerated, temporarily reversing gains.

Using the Decomposition for Forward Decisions​

If you had a bad 2022 in your bond portfolio, decomposing losses helps you decide forward positioning:

Analysis: "I lost 10%. I estimate 70% came from rising Treasury yields (8% loss) and 30% came from credit spread widening (2% loss)."

Implication for 2023:

  • If you believe rates have peaked and will fall, you want more duration to capture gains. But spread risk persists.
  • If you believe spreads stay wide (recession coming), you want less credit exposure. Shift toward Treasuries.
  • If you believe both rates and spreads will improve (Fed will cut, recession averted), hold corporates for gains on both fronts.

Conversely, if you lost money in 2022 entirely due to Treasury yields rising and had no spread losses:

Analysis: "I lost 10% entirely from rates; spreads actually compressed 100 bps, providing modest gains that offset some rate losses."

Implication for 2023:

  • If rates will fall, your current positioning benefited the "unwind" trade.
  • If rates rise further, you'll lose more, unless spreads compress further (unlikely if rates are rising from stronger growth).
  • You're not exposed to recession credit risk; consider if that's intentional or accidental.

Attribution in Fund Reports​

Better bond fund prospectuses break down returns between:

  • Interest income (coupon earned)
  • Price change from rate movement (Treasury yield change × duration)
  • Price change from spread movement (spread change × duration)
  • Other factors (currency if international, convexity, etc.)

Reading a fund's semi-annual report with this decomposition helps you understand what actually drove performance and decide if the fund's management is skilled or lucky.

A fund that reports: "We gained 5% from falling rates and lost 2% from spread widening, net +3%," is telling you the manager was right on rate direction but wrong on credit. This matters for forward outlook.

Building Resilience to Both Risks​

To manage both rate and credit risk:

  1. Diversify across credit quality: Mix high-quality corporates (LQD) with Treasuries (VGSH, BND component). Avoid high-yield concentration unless you have appetite for spread widening.

  2. Ladder maturities: Shorter-duration bonds are safer in rising-rate environments; longer-duration bonds capture more spread compression in falling-rate environments.

  3. Monitor economic indicators: Watch recession probability indices and credit spreads. If spreads widen sharply relative to Treasury yields, credit is repricing risk—consider reducing corporate exposure.

  4. Understand your portfolio's rate/spread sensitivity: Know your fund's duration and spread duration. A broad index fund (BND) has both; a Treasury fund (VGSH) has only rate risk.

  5. Size positions appropriately: If you believe in diversified stocks + bonds for most of your portfolio, use broad bond indices that blend Treasuries and corporates. Reserve high-yield or corporate-heavy funds for a small satellite position if you have strong conviction.

Decomposition Flowchart​

Next​

We've examined spreads as a separate source of risk. But even Treasury yields, free from credit spread risk, contain multiple components: the real risk-free rate, inflation expectations, and compensation for long-term volatility. Understanding this decomposition reveals whether bonds are cheap or expensive and what's really driving yields.