A 30-day bidding window opens next month at the IATA Aviation Carbon Exchange (ACE), giving airlines another opportunity to purchase CORSIA Phase I eligible emissions units.

The November 2026 event — what IATA and Xpansiv call the Next Procurement Event — runs throughout the month. IATA and Xpansiv jointly operate the platform; Xpansiv handles registry connections and settlement.

What does the November window actually unlock?

ACE will list eligible emissions units (EEUs) that satisfy CORSIA Phase I criteria — the Carbon Offsetting and Reduction Scheme for International Aviation, administered by ICAO. Phase I covers the 2024–2026 emissions window. IATA and Xpansiv plan to publish project-level information on October 21, giving buyers roughly six weeks of evaluation runway before bidding opens.

The hard date operators care about: this November event sits inside the Phase I compliance period. Carriers sourcing credits here buy against 2024–2026 emissions, not forward obligations.

The scale is meaningful: Phase I covers three years of international aviation emissions, and ACE runs as IATA's direct-procurement channel under the scheme. Carriers that need additional sourcing options for 2024–2026 obligations now have another structured route before phase accounting closes.

What new tools target procurement friction?

Three features debut with this event:

• Tailored requests for proposals or information, letting airlines set registry, methodology and payment terms inside the request
• Registry custodial services letting carriers transact through ACE sub-accounts without maintaining their own registry accounts
• A deferred payment option that locks in pricing upfront while credits sit in escrow until delivery — available through December 2027

The deferred-payment window runs roughly 13 months — November 2026 through December 2027 — giving airlines more than a year to settle trades against finalized 2026 emissions data. Carriers that need flexibility to align purchases with year-end reporting will lean on this option.

That mirrors how commodity procurement often works in adjacent environmental markets: lock the price, defer delivery. For airlines, the timing matters because 2026 emissions accounting won't be finalized until later in the compliance cycle, well after the November bidding window.

Sub-account custody is the practical unlock for smaller carriers without dedicated registry relationships; it removes a setup barrier that previously kept some participants out of direct procurement.

Who actually needs these units?

CORSIA establishes a framework for addressing international aviation emissions growth through eligible carbon units. Phase I runs 2024–2026, and access to qualifying credits during that window is what IATA calls "an important procurement consideration for airlines."

The Phase I compliance window is the binding constraint. Phase II coverage, scope and credit-eligibility rules for the post-2026 period have not yet been finalized by ICAO. Every remaining Phase I procurement event becomes a high-stakes sourcing opportunity for carriers that missed earlier windows or want to build positions before the rule book changes.

What about ongoing market intelligence?

ACE offers a free weekly CORSIA update listing available units; subscribers can submit bids and counter-bids directly. It's an alternative to waiting for the procurement event cycle and a practical channel for airlines watching price discovery between procurement windows.

What milestone decides what happens next?

Two dates anchor the near-term calendar:

• October 21 — project-level information publishes for the November event
• November 2026 — bidding window opens for Phase I eligible units, closes the same month

Carriers onboarding now can contact [email protected]. After the November window closes, the watch shifts to deferred-payment settlements against 2026 emissions and whether ACE stages a follow-on event in early 2027, before ICAO finalizes Phase II rules.