Duration Gap and Credit Migration in a Rising-Rate Environment
Harbor Point Insurance has $1.2B in invested assets: 65% fixed income with modified duration 6.2 years, 15% public equities, 10% private credit, and 10% cash. Net loss reserves are $940M with an estimated duration of 8.5 years. The CFO forecasts a parallel 150 bp rise in Treasury yields over the next 12 months and a 75 bp widening of investment-grade credit spreads. The equity portfolio has a beta of 1.05 to the S&P 500, and the private credit allocation has a reported duration of 3.0 but limited liquidity. The company's surplus is $260M. The investment committee is considering three actions: (1) extend fixed-income duration to 8.0, (2) add a 10% allocation to 10-year Treasury futures, or (3) increase cash to 20% and shorten duration to 4.5. The board has a surplus-at-risk limit of 20% over one year at 95% confidence. Rating agency capital charges favor Treasuries over corporates. The CIO believes rates will rise but is concerned about a credit cycle.
1. Estimate the first-order surplus impact of the 150 bp rate rise under the current portfolio and under each of the three proposed actions, stating assumptions.
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Assume parallel shifts, no convexity, and that the private credit duration is 3.0. Current asset duration is 0.65 x 6.2 + 0.10 x 3.0 = 4.33. Dollar duration of assets is $1.2B x 4.33 = $5.196B. Liability dollar duration is $940M x 8.5 = $7.990B. Surplus dollar duration is $5.196B - $7.990B = -$2.794B. A 150 bp rise gives -$2.794B x 0.015 = -$41.9M, or -16.1% of $260M surplus. Action 1: fixed-income duration 8.0 gives asset duration 0.65 x 8.0 + 0.30 = 5.50; asset dollar duration $6.600B; surplus dollar duration -$1.390B; impact -$20.9M, or -8.0%. Action 2: add 10% Treasury futures with assumed duration 8.0 and notional $120M; added dollar duration $0.960B; total $6.156B; surplus dollar duration -$1.834B; impact -$27.5M, or -10.6%. Action 3: cash 20%, fixed income 55% at duration 4.5; asset duration 0.55 x 4.5 + 0.30 = 2.775; asset dollar duration $3.330B; surplus dollar duration -$4.660B; impact -$69.9M, or -26.9%, which breaches the 20% surplus-at-risk limit. Credit spread widening would add losses on corporates and is not included above.
2. Critique the CIO's view that rates will rise but a credit cycle may emerge, and recommend a portfolio action.
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The CIO's view is coherent: rates can rise because of inflation or term premium while credit spreads widen because of deteriorating credit conditions. The mistake would be to hedge the rate view with corporate credit risk. Extending duration with corporates would add spread duration just as spreads widen. The better action is Action 1, but implemented with Treasuries rather than corporates, because Treasuries hedge the liability duration and benefit from flight-to-quality while rating agency capital charges favor them. Action 2 also extends duration but introduces futures basis risk, margin calls, and roll cost; it may be useful as an overlay but not as the primary hedge. Action 3 is the worst choice: shortening assets when liabilities have duration 8.5 increases the negative duration gap and breaches the surplus-at-risk limit under the stated rate shock. I would recommend Action 1 using Treasury securities, funded by reducing private credit or cash, and I would separately stress-test a 75 bp spread widening. The board should also monitor private credit liquidity, because its reported duration may understate price sensitivity in a credit cycle.
3. Explain how the recommended action interacts with the board's surplus-at-risk limit and rating agency capital charges.
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The current portfolio loses about 16.1% of surplus for a 150 bp rise before credit spread effects, which is inside the 20% limit but leaves little room for spread widening. Action 1 reduces the rate-only loss to about 8.0%, creating buffer for credit migration and equity volatility. The rating agency capital charge favors Treasuries over corporates, so implementing the duration extension with Treasuries improves both economic hedging and regulatory capital treatment. The action also reduces the mismatch between asset and liability durations from a negative surplus duration of -$2.794B to -$1.390B. However, the board should not treat the 8.0% estimate as complete: a simultaneous 75 bp spread widening on corporate holdings could add a material loss, and equity beta exposure remains. The investment committee should set a combined rate-plus-spread stress test, not just a parallel rate shock, and should confirm that the surplus-at-risk limit is measured on a combined basis. If the combined loss exceeds 20%, the committee should reduce credit exposure or add a credit hedge.