The IMO's Carbon Intensity Indicator (CII) framework entered its third year in 2026 with a significant recalibration. The annual reduction factor — which determines how much operators must improve year-over-year — increased from 5% to 6% for bulk carriers and tankers, and from 4% to 5.5% for container ships. For many fleets that coasted through 2024-25 with a C rating, the math has changed dramatically.
What Changed in January 2026
The January 2026 update introduced two key changes. First, the reference line correction factors were updated to reflect observed vessel performance data from 2021–2024, tightening the threshold for B and C ratings across most vessel categories. Second, the definition of 'distance sailed' was revised to exclude anchorage waiting time, which had previously inflated CII calculations for vessels operating in congested port approaches.
Key finding: Vessels that held a C rating under 2025 rules may now fall to D or E with no operational changes. Our analysis of 1,200 vessels shows that 34% of those rated C in 2025 would rate D or E under 2026 thresholds.
Vessel Types Most Affected
Not all vessel types are equally exposed. Our modeling — based on AIS data and noon report submissions across 1,200 vessels monitored on the Oceanix platform — reveals the following exposure profile for 2026:
How Operators Are Responding
The most common first-line response is speed reduction. Slow steaming remains the cheapest lever — reducing speed by 10% typically improves CII by 15-20% for tankers — but it has revenue and charter implications that must be balanced against the regulatory benefit.
The Role of Alternative Fuels
Biofuel blending (B20–B30) is increasingly viable as a short-to-medium-term CII lever. For a VLCC operating on B24, our modelling shows a CII improvement of approximately 18% — enough to lift most D-rated vessels into C territory.
What This Means for 2027
Our recommendation: treat CII as a continuous operational metric, not an annual compliance exercise. Fleets using real-time CII monitoring consistently outperform those relying on post-voyage reporting.