Aena (AENA)

The RAB-Regulated Airport Network

Spanish airport cash flows turn on regulated-asset-base (RAB) mechanics under DORA, the Spanish airport charge-setting framework, rather than a concession expiry. The network has no single lapse date; the current cycle, DORA II, runs 2022 to 2026 with a pre-tax return on RAB of 7.68%. Net debt was €5,509 million at 31 December 2025, consistent with the leverage ratio above.

Cash flows come from regulator-approved returns on RAB and per-passenger charges rather than uncapped demand-risk tolls with a contractual end date. International PPP assets reintroduce finite-life demand risk: London Luton runs to 18 September 2032, roughly 6.7 years out. The RAB regulation guide walks through DORA mechanics against Auckland's Part 4 information-disclosure model and UK Heathrow's H7 context.

Business Overview

The Spanish airport system is the core earnings engine. Passenger growth of +4.2% in FY2025 sits above the +1.1% Auckland print and below Vinci Airports' +5.0%. Volume-growth assumptions use ~1.3× GDP/income elasticity for developed airports; the traffic linkage guide contrasts that with mature toll roads at ~1.0× GDP.

International exposure adds PPP finite-life assets. The Luton concession ends in September 2032 and sits outside the Spanish regulatory cycle. Galeão (Rio) would add a second: on 30 March 2026 Aena won the auction for 100% of the airport's concession company at BRL 2,900 million, for a concession that runs to May 2039. As of Aena's H1 2026 results on 29 July 2026 the purchase had not completed; Aena expects completion in the second half of 2026, once regulatory approvals and the other sale conditions are met. Both reintroduce demand-risk and expiry-cliff analysis onto a balance sheet that is otherwise regulated-cycle driven.

DORA II ends in 2026. For the next cycle, DORA III (2027-2031), Aena proposed a 9% WACC and the regulator CNMC recommended 7.4% in June 2026; the Council of Ministers set 8.32% pre-tax on 15 September 2026. That rate sets the allowed return on RAB for the next regulatory period.

How Regulated Airport Economics Work Here

Regulated returns follow a WACC-times-RAB formula, applied here to average RAB of €9,387.1 million. IMAAJ, the visible per-passenger charge line in Aena's filings, sits alongside that return. Tariff escalators on toll roads (French CPI floors, Transurban's deed floors) work differently; the escalators guide maps the inflation-linkage zoo across transport infrastructure.

EBITDA margin of 59.3% sits in the regulated-airport band, roughly 59-69% across the comp set, below Auckland's derived EBITDAFI margin but above Getlink's 53.9%. Net debt/EBITDA of 1.46× matches Vinci at 1.4×, both comfortably under a conservative 3× threshold.

IFRIC 12, the accounting standard for service concessions, still applies to the airports Aena runs under concession abroad, chiefly the Brazilian airport groups, even where the Spanish network runs on DORA. The ex-IFRIC 12 EBITDA margin of 61.4% shows how concession accounting moves the reported ratio without changing the cash actually collected on the regulated Spanish system.

Valuation Framework

Spanish network valuation works from a roll-forward of RAB, the allowed WACC and the per-passenger charge path through the regulatory cycle, rather than a single expiry DCF. A finite-life DCF with zero terminal value applies separately to Luton and the other PPP concessions. The finite-life DCF guide explains when perpetuity multiples fail; the failure mode here runs the other way for the core network, which has no expiry, versus Luton's short remaining life.

EV/EBITDA works only as a cross-check, never the primary method. This analysis treats ~10-14× as typical for regulated or availability-style concessions and ~12-16× for demand-risk toll roads. Net debt/EBITDA is a leverage figure rather than a valuation multiple, and Aena's 1.46× sits well inside a conservative screening level.

What to Watch in the Financials

DORA III from 2027. The Council of Ministers set an 8.32% pre-tax WACC for 2027-2031 on 15 September 2026, above DORA II's 7.68%. On an unchanged asset base a higher allowed WACC lifts the return on RAB: 0.64 points on €9,387.1 million is about €60 million a year before tax.

Passenger growth versus IMAAJ. Volume grew while the per-passenger charge held flat, so FY2025 revenue growth was mostly volume-led. Regulatory resets can change the charge independently of traffic.

Luton expiry (~6.7 years). Short remaining life on the international PPP book mirrors Vinci Escota as a cliff asset inside a longer-regulated core.

Galeão completion. Not completed as of 29 July 2026; Aena expects completion in the second half of 2026. The concession runs to May 2039, so once consolidated it adds Brazilian demand risk with its own expiry clock.

Peer Context

Aena's published RAB, WACC and IMAAJ framework is fuller than Auckland's Part 4 disclosure model, where the Commerce Commission targeted a 7.82% return against Aena's own 7.68% pre-tax WACC on RAB. Vinci Airports (+5.0% passengers, 63.4% margin, Lyon to 2047) mixes regulated and demand exposure; Aena's Spanish system is more purely regulated, at a higher passenger scale (384.8M vs 334M) and similar leverage (1.46× vs 1.4×).

Key Risks

Regulatory reset risk (DORA III). Allowed WACC and RAB recognition are negotiated between the company and its regulator, not set by the market. DORA III fixed the WACC at 8.32% for 2027-2031 (set 15 September 2026), so the next reset of the allowed return falls on the period from 2032.

International PPP expiry. Luton ~6.7 years remaining introduces finite-life reversion on a slice of the group while the Spanish network continues on regulatory cycles.

Passenger cyclicality. Even regulated airports bear volume exposure on aeronautical and commercial revenues adjacent to the core charge mechanics.

Concentration in Spanish traffic. Spain 321.6 million of 384.8 million passengers ties results to domestic tourism and airline capacity cycles.