EU ETS mechanics
What is TNAC in the EU ETS?
TNAC sets MSR intake. Desks that mis-read the stock mis-price the reform path.
Updated 2026-08-05 · Model output for professionals · Not investment advice
The short answer
TNAC means Total Number of Allowances in Circulation. It is the Commission’s official stock metric for EU Allowances (EUAs) still available in the market after accounting for verified emissions, cancelled units, and other defined adjustments.
It is not the same as open interest on ICE, bank holdings, or a broker inventory. TNAC is the policy stock that feeds the Market Stability Reserve (MSR).
Why TNAC moves EUA fair value
When TNAC sits above the upper MSR threshold, a share of future auction volumes is diverted into the reserve. When it falls below the lower threshold, allowances can be released. That changes forward supply, not just the headline story.
Reform packages that change free allocation, LRF, or MSR parameters change how today’s TNAC maps into tomorrow’s auction calendar. That is why Scenario Desk turns policy into a balance path, then a calibrated fair value, instead of a single narrative.
What desks watch next
Annual TNAC publications, auction calendars, and any legislative text that rewrites MSR thresholds or invalidation rules. Pair the stock with Day+1 demand: a tight stock with rising power burn is a different trade than a loose stock with weak industry.
FAQ
- Is TNAC the same as EUA open interest?
- No. Open interest is exchange positioning. TNAC is the Commission’s circulation stock used for MSR intake and release rules.
- How often is TNAC published?
- The Commission publishes TNAC on a defined annual schedule. Desks also track interim proxies from auctions, surrenders, and verified emissions, knowing those proxies are not the official print.