High yield bonds: how non-investment-grade credit behaves in a portfolio

High yield bonds—also called junk bonds—are debt issued by companies whose credit rating sits below investment grade. They offer higher coupons than Treasury or investment-grade corporate debt, in compensation for higher default risk and the resulting equity-like correlation pattern in downturns. As a portfolio asset class, high yield sits between traditional fixed income and equity in both expected return and risk profile.

What high yield bonds are

A high yield bond is one rated below investment grade by the major credit rating agencies—BB+ or lower by Standard & Poor's and Fitch, Ba1 or lower by Moody's. The threshold separates issuers considered creditworthy enough to be a prudent investment for institutional capital from those whose default risk is high enough to require explicit compensation in the coupon.

The asset class includes several distinct issuer types. Original-issue high yield includes leveraged-buyout financing, growth-stage companies whose business models do not yet support investment-grade ratings, and companies in distressed industries. Fallen angels are formerly investment-grade issuers whose credit deteriorated to high yield ratings—often producing technical buying opportunities when forced selling by investment-grade-only mandates pushes prices below fundamental value. Distressed debt is the deepest tier of the asset class, where bonds trade at deep discounts to par and the analytical question becomes default-and-recovery rather than yield-and-duration.

The market is large and active. The US high yield market alone is approximately USD 1.5 trillion in notional, accessible through both corporate bond issues and high yield bond ETFs that have grown into the tens of billions of assets each.

How they work

The mechanics of a high yield bond are similar to those of investment-grade debt: defined coupon, defined maturity, defined seniority in the capital structure. The differences are quantitative—higher coupons, shorter typical maturities, more complex covenants protecting the bondholder against actions by the issuer that would impair credit quality.

Default rates are the headline risk. The Moody's annual default rate study reports long-run averages of approximately 4% for speculative-grade issuers, with substantial variation by year—default rates exceeded 10% in 1991, 2001–2002, and 2009. Recovery rates conditional on default average approximately 40% for senior unsecured high yield, meaning the realised loss on a defaulted senior unsecured bond is approximately 60% of par.

Combining default rate and recovery rate produces the long-run credit loss: 4% × 60% = 2.4% per year on average. This is the figure the high yield coupon must clear to deliver a positive expected return above investment grade. Historical high yield coupons over investment-grade equivalents have been approximately 3–5 percentage points, leaving a residual credit risk premium of approximately 1–3 percentage points after expected losses.

What the evidence shows

Long-run total returns on US high yield have averaged approximately 7–8% per year nominal over multi-decade samples (1980–2020), compared with approximately 5–6% on investment-grade corporate bonds and approximately 4–5% on Treasuries. The high yield premium has been real but has compressed in calm regimes when investors chase the higher coupon and bid prices up—most visibly in the 2003–2007 and 2017–2019 windows, both of which preceded notable drawdowns.

The asset class's drawdown profile is its defining risk feature. The 2008 high yield index drawdown was approximately 33% peak-to-trough, behaviour much closer to equity than to traditional fixed income. The 2020 COVID drawdown produced a similar but shorter-duration episode (peak drawdown approximately 22%, fully recovered within the year). In both cases, the asset class behaved more like equity than like investment-grade fixed income—its correlation with equity rises sharply during stress periods even when it is moderate in calm regimes.

The flip side is the recovery profile. Asness, Israelov, and Liew (2011) and others have documented that high yield drawdowns recover faster than equity drawdowns of similar magnitude, because the coupon income continues to accrue through the drawdown and the bond pulls back to par at maturity in the absence of default. Investors who held through 2008 captured a meaningful recovery and total return over the subsequent five years.

Limitations and trade-offs

The asset class's equity-like behaviour in stress means it provides less diversification against equity drawdowns than its fixed income classification would suggest. A portfolio that uses high yield as part of the "safe" allocation can find that the safe allocation falls 20–30% precisely when the equity allocation falls similarly—a correlation pattern that defeats the purpose of diversification.

Liquidity is meaningfully worse than for Treasuries or investment-grade credit. Bid-ask spreads in the high yield market widen substantially during stress, and the underlying bonds can become difficult to trade at reasonable prices. ETF wrappers provide retail-investor liquidity but the underlying pricing pressure during stress is not eliminated by the wrapper—high yield ETFs can trade at meaningful discounts to NAV during the worst episodes.

Concentration is a structural feature. High yield issuance is concentrated in specific sectors (energy, telecom, retail, healthcare) and the resulting indices and ETFs carry meaningful sector concentration. The 2014–2016 energy-sector drawdown produced a high yield drawdown that was driven primarily by oil-and-gas issuer distress; investors with high yield allocations effectively bore commodity risk through their fixed income exposure.

High yield bonds in pfolio

pfolio's fixed income universe includes high yield corporate bond ETFs alongside investment-grade corporate and government bond ETFs. The high yield exposure can be added to a portfolio with explicit attention to its higher equity-correlation in downturns; the asset class behaves more like equity than like investment-grade fixed income in most stress scenarios. Performance and risk metrics are visible in pfolio Insights.

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