Debt Mutual Funds: Credit Risk vs Duration Risk Explained

Debt funds carry two very different risks that can dent NAV: duration risk from interest-rate moves, and credit risk from a specific issuer weakening. This guide separates the two, shows how each shows up in NAV, and how to build an evidence file if something goes wrong.

Credit risk vs duration risk: what actually moves the NAV

Duration risk is the market-wide effect of interest-rate moves on bond prices: when yields rise, existing bond prices fall, and by how much depends on the fund’s average duration. A fund with roughly 5 years of modified duration loses close to 5% of its bond-portfolio value for every 1 percentage-point rise in yields (price change is approximately −duration × change in yield), even if every bond it holds is top-rated AAA or G-Sec paper. This risk touches every bond fund; only overnight and ultra-short-duration funds are largely insulated from it.

Credit risk is issuer-specific: the risk that a particular bond’s issuer defaults, gets downgraded, or has to be marked down. SEBI’s mutual-fund categorisation rules only let a scheme call itself a “Credit Risk Fund” if at least 65% of its debt portfolio sits in AA-and-below-rated corporate bonds — a different category from a Corporate Bond Fund (predominantly AA+ and above) or a Banking & PSU Fund. A downgrade or default hits NAV directly through that one holding’s valuation, independent of what interest rates are doing, and can also trigger redemption pressure if it is large relative to the scheme (the 2018 IL&FS defaults and the six Franklin Templeton credit-oriented schemes wound up in April 2020 are the two most-cited Indian examples).

Worked example

Two funds each hold ₹100 of bonds. Fund A, a G-Sec/AAA duration fund with a 5-year modified duration, sees yields rise by 1 percentage point; its bond value falls to roughly ₹95 — a pure duration-risk loss, with no change in credit quality. Fund B, a credit-risk fund, holds a bond from an issuer downgraded from AA to BB; the bond is marked down to, say, ₹70 to reflect the higher default risk — a credit-risk loss unrelated to interest rates. A fund can take both losses at once if a downgraded issuer’s bond also happens to be long-duration.

1. Why this matters

Most retail investors do not lose money only because markets fall. They lose money because of leverage, costs, poor product understanding, fake claims, hidden conflicts, liquidity traps, weak due diligence and delayed complaints. Investor protection begins before the transaction.

For the connected rule, example or next step, see Debt Mutual Fund Risk Checklist: Duration, Credit and Liquidity Before Investing.

This article is not a recommendation. It is a practical safety playbook: verify registration, read documents, understand risk, preserve evidence and escalate through official routes where needed.

2. Verified-source-backed approach

• Duration risk and credit risk are different things — check a debt fund’s average maturity/duration AND its credit-quality mix separately before investing.
• Use official SEBI/exchange/AMC/platform/product sources before acting.
• Keep statements, contract notes, screenshots, ticket IDs and product documents.
• Avoid guaranteed-return claims, anonymous tips and unregistered advice.

For the connected rule, example or next step, see PMS vs Mutual Funds: Customisation, Cost and Concentration.

3. Practical action checklist

• Read scheme objective and riskometer.
• Check expense ratio and benchmark.
• Review top holdings and concentration.
• Understand credit/duration risk for debt funds.
• Compare performance across cycles, not one month.

4. Evidence file checklist

5. Common mistakes

• Investing because a screenshot or influencer shows profit.
• Treating GMP, tips or target prices as verified source material.
• Ignoring costs, taxes, slippage and liquidity.
• Using emergency money for leveraged or illiquid products.
• Not checking whether the adviser/intermediary is registered.
• Complaining without evidence or without first approaching the entity where required.

6. Red flags

• Guaranteed return or no-loss promise.
• Pressure to transfer money quickly.
• Personal bank account instead of regulated entity account.
• Withdrawal blocked unless more fees are paid.
• Product document not shared.
• High yield without credit, liquidity or collateral explanation.
• Anonymous Telegram/WhatsApp admin giving buy/sell calls.

7. Finin2min takeaway