Airport Debt Portfolio Management and Refunding Strategies
Optimizing debt service, managing refunding decisions, and evaluating multi-lien structures
A reference for airport and aviation finance professionals
Prepared by DWU AI · Reviewed by alternative AI · Human review in progress
An AI Product of DWU Consulting LLC
March 2026
DWU Consulting LLC provides specialized municipal finance consulting services to major North American airports, aviation authorities, and municipal issuers. This article is part of the DWU AI research library, a collection of reference materials for airport finance professionals.
Scope & Methodology
This article examines the management of airport revenue bond portfolios with emphasis on refunding decision-making, structural alternatives to tax-exempt advance refunding (post-2017), portfolio metrics, and the interaction between debt management and airline rate-setting. Analysis draws from published bond official statements, airport debt policies, rating agency credit opinions, and securities law sources. All examples reference verifiable transactions and disclosed policy documents.
Bottom Line
Airport debt portfolios of $1–$10+ billion are actively managed assets. Tax-exempt advance refunding, eliminated by the Tax Cuts and Jobs Act of 2017, has been replaced by taxable advance refunding, forward delivery bonds, and tender offers. Refunding decisions turn on net present value (NPV) savings thresholds set by airport debt policies (e.g., SFO requires 3% NPV savings; Austin applies 4.25%) and timing relative to interest rate cycles. Under compensatory rate structures, refunding savings flow directly to airline cost bases, connecting portfolio management to competitive positioning.
The Debt Portfolio as a Managed Asset
An airport's outstanding debt portfolio—the aggregate of all bond series, notes, and credit facilities—is not a static obligation. It is an asset that can be managed through refunding transactions, lien management, amortization design, and capital planning to reduce borrowing costs, reshape debt service profiles, and preserve financial flexibility.
At the largest U.S. airports, the outstanding portfolio can exceed $10 billion in par amount. Los Angeles World Airports (LAWA) had $10.8 billion in outstanding airport revenue bond debt as of its 2024 authorization request, with $3 billion in additional issuance authorized through FY2028 (May 22, 2024). Phoenix Sky Harbor International Airport (PHX) carried $1.86 billion across senior-lien ($610 million) and junior-lien ($1,253 million) obligations as of May 2025. San Francisco International Airport (SFO) issued $924.7 million in Second Series Revenue Refunding Bonds in 2024 alone (May 2024).
Managing a portfolio of this scale requires analyzing every outstanding series against current and projected interest rates, evaluating optional redemption dates, assessing the interaction between lien tiers, and timing new money and refunding issuances to optimize the airport's aggregate debt service profile. Without this analysis, refunding opportunities may be overlooked, potentially leading to higher aggregate interest costs.
Core Portfolio Metrics
Airport finance teams and municipal advisors track several metrics to evaluate portfolio health and identify refunding opportunities:
| Metric | What It Measures |
|---|---|
| Weighted Average Coupon Rate | Average stated coupon across all outstanding par, weighted by par amount per maturity |
| True Interest Cost (TIC) | Discount rate equating present value of all future principal and interest payments to the purchase price paid by the underwriter; accounts for time value of money |
| Net Interest Cost (NIC) | Total future interest payments less any premium, divided by bond dollar-years; does not account for time value |
| All-In Cost (AIC) | TIC including issuance costs (underwriter discount, bond counsel, financial advisor, rating agency fees, trustee fees) |
| Maximum Annual Debt Service (MADS) | Highest single-year debt service on all outstanding obligations; used for DSRF sizing and additional bonds test calculations |
| Debt Service Coverage Ratio (DSCR) | Net Revenues ÷ Annual Debt Service; measures the margin of revenue above debt service obligations |
| Days Cash on Hand | Unrestricted cash and investments ÷ (annual operating expenses / 365) |
| Fixed / Variable Rate Mix | Percentage of portfolio at fixed vs. variable rates; variable-rate exposure introduces interest rate risk |
| AMT / Non-AMT Mix | Percentage of par outstanding subject to the Alternative Minimum Tax; AMT bonds carry wider spreads due to a narrower investor base |
TIC has replaced NIC as the primary measure for awarding competitively bid bond sales because it accounts for the time value of money—a $1 million payment in Year 1 is more costly than the same payment in Year 20.
The Refunding Decision
Current Refunding vs. Advance Refunding
The Internal Revenue Code draws a bright line at 90 days. Under IRC § 149(d)(5), a refunding is "advance" if the refunding bonds are issued more than 90 days before the redemption of the refunded bonds. A refunding where the refunded bonds are redeemed within 90 days is a "current" refunding.
This distinction became the defining constraint on airport refunding strategy after December 31, 2017.
The TCJA Elimination of Tax-Exempt Advance Refunding
Section 13531 of the Tax Cuts and Jobs Act of 2017 (P.L. 115-97) repealed the exclusion from gross income for interest on bonds issued to advance refund another tax-exempt bond after December 31, 2017. Prior to the TCJA:
- A bond issued after 1985 could be advance refunded once on a tax-exempt basis (IRC § 149(d)(3)(A)(i)).
- Issuers used advance refundings to lock in lower interest rates years before the refunded bonds' call date, eliminating the risk that rates would rise before the call date arrived.
After December 31, 2017, tax-exempt advance refunding is no longer available. An airport issuer with callable bonds carrying a 5.00% coupon and a call date three years away cannot issue tax-exempt refunding bonds today; it must wait until 90 days before the call date (current refunding) or pursue one of several alternative structures.
Multiple legislative proposals have sought to restore tax-exempt advance refunding since 2018, including the LOCAL Act (S. 479, 2021), the LIFT Act (H.R. 8396, 2024), and the Investing in Our Communities Act. As of March 2026, none have been enacted.
NPV Savings Threshold
The primary financial objective of a refunding is to reduce the net present value (NPV) of debt service payments on the refunded bonds. Airport debt policies and governing body resolutions set minimum NPV savings thresholds that a proposed refunding must meet before management will proceed.
Two published examples:
- San Francisco International Airport (SFO): SFO's debt policy requires that refunding bonds issued solely for debt service savings produce estimated NPV savings of at least 3% of the par amount of the refunded bonds — or at least 1% if, in the judgment of the airport's municipal advisors, a future refunding is unlikely to realize greater savings (February 20, 2024).
- City of Austin — Austin-Bergstrom International Airport (AUS): Austin's bond ordinance applies a 4.25% NPV savings target. Austin's Series 2025 (AMT) refunding of $244.5 million of Series 2014 (AMT) bonds produced estimated NPV savings of 7.16%, or $17.5 million (March 6, 2025).
These thresholds serve as a discipline: they prevent the issuer from incurring issuance costs for marginal savings that could be exceeded by waiting for a more favorable rate environment.
Post-TCJA Refunding Alternatives
The elimination of tax-exempt advance refunding created demand for substitute structures. Four primary alternatives have emerged since 2018: