Pension Fund Investment Strategies
Defined-benefit pension funds face a unique challenge: they must generate enough return to fund future benefit payments while managing the risk that assets fall short of liabilities. The strategies they use are more sophisticated — and more constrained — than most investment mandates.
The Funded Status Problem
A pension fund's funded status is the ratio of assets to liabilities. A 100% funded plan has exactly enough assets to cover all future benefit obligations. Most public pension funds in the US are underfunded — the average funded ratio for state and local pensions is around 70–75%, meaning they have a significant gap to close.
This gap creates a fundamental tension: the plan needs to take investment risk to generate returns and close the gap, but taking too much risk could make the gap worse if markets decline. The investment strategy must balance these competing pressures.
Core Pension Investment Strategies
Liability-Driven Investing (LDI)
Match the duration and cash flow profile of liabilities using long-duration bonds and interest rate swaps. Reduces funded status volatility.
Return-Seeking Portfolio
Equities, private equity, and real assets sized to close the funding gap. Managed separately from the LDI sleeve.
Glide Path De-risking
As funded status improves, shift assets from return-seeking to LDI. Locks in gains and reduces risk as the plan approaches full funding.
Portable Alpha
Use derivatives to gain beta exposure cheaply, freeing capital to invest in alpha-generating strategies. Common in large public pensions.
Liability-Driven Investing in Practice
LDI is the dominant framework for corporate pension funds. The liability — the present value of future benefit payments — is sensitive to interest rates: when rates fall, the liability grows. LDI hedges this sensitivity by holding long-duration bonds and interest rate swaps that increase in value when rates fall, offsetting the liability increase.
A typical LDI implementation might hedge 50–80% of interest rate sensitivity using a combination of long-duration Treasuries, corporate bonds, and interest rate swaps. The remaining capital is allocated to return-seeking assets — equities, private equity, real assets — to generate the returns needed to close the funding gap.
Public vs. Corporate Pension Funds
Corporate pension funds (governed by ERISA) have strong incentives to fully fund and de-risk because underfunded plans require higher contributions that affect earnings. Many corporate plans have adopted aggressive LDI strategies and are now well-funded or even overfunded.
Public pension funds (state and local government plans) are not subject to ERISA and often use higher assumed return rates — typically 7–7.5% — to minimize required contributions. This creates political pressure to take more investment risk, which has led many public plans to increase allocations to private equity and alternatives.
The Role of Private Markets
Large public pension funds — CalPERS, CalSTRS, the Ontario Teachers' Pension Plan — have become major allocators to private equity, infrastructure, and real estate. These assets offer higher expected returns than public markets and provide inflation protection through real asset exposure.
The Ontario Teachers' model is particularly notable: the fund manages much of its private equity and infrastructure in-house, reducing fees and building deep operational expertise. This approach requires significant scale and talent but has delivered strong long-term results.