PSU Bond Fund vs Corporate Bond Fund: Credit Risk, Yield Spread and the AAA-vs-AA Trade-Off

Bond funds are the workhorse of an Indian fixed-income allocation, yet two SEBI-defined categories sitting next to each other on every fund-house factsheet are routinely conflated by retail investors. PSU and Banking Debt Funds park money in AAA-rated paper issued by government-owned entities. Corporate Bond Funds chase the next rung down — AA+ and above private credit — for an extra 50-70 basis points of yield. With the Reserve Bank of India holding the repo rate at 5.25% on 8 April 2026 after a 125 bps cumulative cut through 2025, the spread question matters more than it has in three years.

The trade-off looks simple on paper. AAA carries near-sovereign credit comfort because the issuer is the Government of India in disguise — Power Finance Corporation, REC, NABARD, NHAI, NHB. AA+ carries more carry but adds genuine private-credit risk: a Vodafone Idea downgrade or an IL&FS-style default can cut a percent off your NAV in a single session. Add the post-2023 tax regime that strips both products of any long-term capital gains relief, and the maths shifts in ways most factsheets do not show.

Side-by-Side Comparison

Both categories are defined by the SEBI Categorisation and Rationalisation Circular of 6 October 2017, which collapsed hundreds of overlapping schemes into 36 standardised buckets. The relevant rules:

• Banking & PSU Fund: minimum 80% of assets in debt instruments of banks, public sector undertakings, public financial institutions and municipal bonds.
• Corporate Bond Fund: minimum 80% in corporate bonds rated AA+ and above.

The issuer universe and credit ceiling are the two structural differences. Everything downstream — yield, default risk, NAV volatility, even tax — flows from those two parameters.

The yield gap is real but it is not free money. The 2018 IL&FS default and the April 2020 Franklin Templeton wind-up of six debt schemes both originated in the AA-and-below pocket — and even the AA+ end of that pocket saw mark-to-market hits because dealer bids vanished overnight. PSU paper was largely untouched in both episodes because the underlying issuers were state-owned and the secondary market never lost confidence in their ability to pay.

Where the Spread Comes From

The 50-70 basis-point spread is not a manager skill premium. It is a credit risk premium that bond markets quote daily on FIMMDA's reference yield curves. As of early May 2026, a 5-year AAA PSU bond like a NABARD or PFC paper trades at a yield-to-maturity of roughly 7.30%. A 5-year AA+ corporate paper from a private issuer of comparable duration trades closer to 7.95%. The 65 bps gap is the bond market's price for the additional probability of default, the additional probability of rating migration to AA or below, and the additional liquidity premium because the paper trades less frequently.

The spread is also cyclical. It compresses in benign credit environments — 2024 saw spreads of just 30-40 bps during the rate-cut anticipation phase — and widens sharply when corporate balance sheets come under stress. During the April 2020 panic, AA+ to AAA spreads briefly hit 250 bps before SEBI's regulatory backstops and RBI's targeted long-term repo operations restored functioning. Investors who bought corporate bond funds at the wider spread captured outsized returns over the next 18 months. Investors who panicked and switched to PSU funds at the same point locked in the loss.

For the equity comparison angle, our recent piece on equity savings vs balanced advantage funds walks through how the same risk-premium logic plays out on the equity side of a hybrid mandate.

Tax Treatment

This is where the post-2023 reforms collapse the strategic difference between the two categories — and where most retail investors are still operating on outdated assumptions.

The Finance Act 2023 inserted Section 50AA into the Income-tax Act, effective 1 April 2023. The provision deems any gain from a 'specified mutual fund' to be a short-term capital gain, irrespective of holding period. The original definition captured any fund with not more than 35% in domestic equity. The Finance (No.2) Act 2024 refined this: a 'specified mutual fund' is now one that invests more than 65% of its assets in debt and money market instruments.

Both PSU and Corporate Bond Funds clear that 65% threshold by an enormous margin — they hold 95-100% in debt by mandate. Consequently:

• All gains, regardless of holding period, are added to your total income.
• Tax is charged at your applicable slab rate.
• There is no long-term capital gains rate of 12.5%.
• There is no indexation benefit on the cost of acquisition.
• TDS at 10% applies on redemption proceeds above Rs 5,000 if you do not file Form 15G/15H.

The practical consequence is that an investor in the 30% slab loses 31.2% of every rupee of gain to the exchequer. A PSU fund returning a gross 7.30% delivers a net 5.02% to a 30%-slab investor. A corporate bond fund returning a gross 7.95% delivers a net 5.47%. The 65 bps gross spread shrinks to 45 bps net of tax — and that is before the AMC's expense ratio, which on the corporate bond side runs 5-15 bps higher because of the credit-research overhead.

For investors in the 5% slab — pensioners, students with fellowship income, low-earning spouses — the maths flips dramatically. The same 7.95% corporate bond gross return retains 7.63% post-tax, against PPF's tax-free 7.10%. Use the SIP calculator to see how a Rs 25,000 monthly contribution to a corporate bond fund compounds over 10 years at a net 7.6% versus PPF at 7.1%, and the corporate bond route wins by roughly Rs 1.4 lakh on a Rs 30 lakh corpus — but only if the saver actually sits in a low slab.

For anyone considering a one-shot deployment from a maturing FD or property sale, the lumpsum calculator lets you test Rs 10 lakh or Rs 25 lakh deployments across both categories and see the post-tax delta. And for a benchmark against the assured-return floor of small savings, the PPF calculator shows what 7.1% tax-free compounds to over 15 years.

Who Should Pick Which

The 'better' fund is a function of your slab, your horizon, your liquidity needs and your tolerance for a 1-2% NAV drawdown in a credit event. Here is the framework I use when sketching debt allocation for clients.

Pick a PSU & Banking Debt Fund if you:

• Are in the 30% slab and treat your debt allocation as a stability anchor rather than a return engine. After 31.2% tax, you are giving up so much of the return that paying for incremental credit risk on top makes little sense.
• Have a 2-4 year horizon and need the lowest possible mark-to-market volatility outside of liquid funds. PSU paper rarely sees credit-spread shocks; the only NAV mover is the rate cycle, which you can model.
• Allocate to debt as the safe sleeve of an asset-allocation model — the role here is principal protection, not yield maximisation.
• Are a retiree drawing a systematic withdrawal plan and cannot afford a sudden 1.5% NAV cut in a credit-stress month, even if it reverses over 90 days.
• Hold money that may be redeployed to equity on a market correction. PSU paper is liquid enough to redeem within T+1 in size, even when the market is panicking.

Pick a Corporate Bond Fund if you:

• Sit in the 0%, 5% or 20% slab. The post-tax pickup is meaningful enough to compensate for the small additional credit risk, and your tax leakage is low enough that gross yield matters more than tax efficiency.
• Are running a 4-7 year horizon with no near-term liquidity need. A 12-month credit shock is recoverable over that window; a 90-day mark-to-market hit is not painful if you are not redeeming.
• Want a direct vehicle for the AA+ universe without picking individual bonds — the diversification across 30-50 issuers is hard to replicate in a personal demat portfolio.
• Use debt as a 'medium volatility, medium return' building block rather than a pure capital-preservation sleeve.
• Already hold sovereign and PSU exposure through PPF, EPF, NPS or G-Sec funds, and want to layer private-sector credit on top.

Pick neither if you:

• Have a horizon under 12 months. Use a liquid fund or overnight fund. Both PSU and corporate bond funds carry duration risk that can wipe out a year's coupon if rates surprise on the upside.
• Are in the highest surcharge bracket. The new tax regime caps surcharge at 25% (down from the old 37%), but combined with the 30% slab and 4% cess, your effective rate on any fresh debt fund redemption is 39%. Tax-free instruments — sovereign gold bonds held to maturity, PPF, EPF voluntary contributions up to the Rs 2.5 lakh threshold — beat any after-tax debt fund return at this slab.
• Need explicit Section 80C cover. ELSS is the only mutual fund category that qualifies, and only under the old regime. The NPS Tier 1 vs Tier 2 comparison explains where retirement-account contributions fit when 80C is your binding constraint.

Real-World Implementation

A practical allocation pattern I have seen work well for clients in the 30% slab and a 5-7 year horizon: split the debt sleeve 60-40 between a PSU fund and a corporate bond fund. The PSU sleeve handles capital preservation and rebalancing-source-of-funds during equity drawdowns. The corporate sleeve captures the spread and absorbs the residual credit-risk premium without dominating the portfolio.

For anyone moving large pots — say a Rs 50 lakh deployment from a maturing FD — staggering the entry over 4-6 months via STP from a liquid fund is structurally safer than a single-day lumpsum. Bond NAVs move with yields; entering across multiple yield prints averages your effective entry yield much like equity SIPs average price. The same logic applies symmetrically on exit: SWP rather than full redemption when the goal date approaches, to avoid printing a one-day NAV that happens to coincide with a yield spike.

For a side-by-side asset comparison that includes the real-estate alternative many investors weigh against debt, the REIT vs rental property analysis benchmarks yield-with-liquidity against capital-locked physical exposure.

Risk Events to Watch in FY 2026-27

Three credit risks sit on the radar through the rest of this financial year, and all three matter more for corporate bond funds than for PSU funds.

• NBFC liquidity: The RBI's risk-weight tightening on bank lending to NBFCs in late 2024 has begun showing up in NBFC bond spreads. Even AAA-rated NBFC paper is trading 15-20 bps wider than equivalent PSU paper, indicating the market sees structural-liquidity risk that the rating does not capture.
• Power-sector receivables: Several state DISCOMs are running aged dues to PSU power generators. While the underlying PSU bonds remain AAA, any RBI scheme to address DISCOM stress could create temporary mark-to-market noise.
• Real-estate-linked corporate paper: A handful of AA+ corporate issuers in the diversified-conglomerate bucket carry sizeable real-estate inventory exposure. Builders' completion delays could pressure the parent-level credit metrics that underpin the bond rating.

None of these is at the level of the 2018 or 2020 events, but they justify the existence of the spread. PSU funds get paid less because they are not in the path of these specific risks.

FAQ

Are PSU bond funds completely risk-free?

No. They invest in AAA-rated debt of public sector undertakings, public financial institutions and banks — but they are not sovereign and they are not guaranteed by the Government of India. The schemes still carry interest-rate risk, which means the NAV will fall when bond yields rise. They are credit-safer than corporate bond funds, not credit-free.

What is the minimum credit rating for a SEBI-categorised corporate bond fund?

Per the SEBI scheme categorisation circular of October 2017, a Corporate Bond Fund must invest at least 80% of its assets in corporate bonds rated AA+ and above. It cannot hold sub-investment-grade or unrated paper as part of that 80% bucket.

How are PSU and corporate bond funds taxed after April 2023?

Both are 'specified mutual funds' under Section 50AA because more than 65% of their portfolio is in debt. All gains, irrespective of holding period, are added to your total income and taxed at slab rate. There is no long-term capital gains rate and no indexation benefit on units bought on or after 1 April 2023.

Is the 50-70 bps yield spread between AAA PSU and AA+ corporate paper worth the extra credit risk?

It depends on the rate cycle and your horizon. In a falling-rate environment with stable corporate balance sheets, the extra spread compounds meaningfully over five years. In a tightening cycle or a credit-stress event — Franklin Templeton in April 2020, IL&FS in 2018 — the AA+ universe can see sharp NAV cuts that wipe out years of spread.

Can these funds hold government securities?

Yes, but only as a residual allocation. The SEBI category mandate fixes the minimum 80% in PSU debt or corporate bonds respectively. The remaining 20% is typically deployed in G-Secs, treasury bills, repo or cash to manage liquidity and duration.

Which is better for an emergency corpus — PSU bond fund or corporate bond fund?

Neither is ideal. Both run a Macaulay duration of 2-4 years, so the NAV moves materially with yield changes. For an emergency corpus, a liquid fund or an overnight fund is structurally safer because the underlying paper matures in 91 days or less.

Do PSU bond funds qualify for any tax benefit under Section 80C?

No. Only Equity Linked Savings Schemes (ELSS) qualify for the Section 80C deduction up to Rs 1.5 lakh — and only in the old tax regime. Open-ended debt funds, including PSU and corporate bond funds, do not qualify.