Open-weights gap to the closed frontier (ECI points)
Gap in Epoch Capabilities Index points between the best closed-weights model and the best open-weights model, measured at each open-weights release. Derived metric open_vs_closed_gap.
Reason through thisThe reading
Measured on Epoch's composite index, so it follows the benchmarks Epoch runs; a gap in points is not a gap in months.
97 readings drawn from the derived metric open_vs_closed_gap; 149 observations in the evidence.
Derived (open_vs_closed_gap) from: Epoch AI benchmarks and Capabilities Index. Epoch AI, Benchmarking Hub and Epoch Capabilities Index (CC BY 4.0).
The numbers
| as of | reading | value | record |
|---|---|---|---|
| 2026-10-17 | — | 10.2 index | measured |
| 2026-10-15 | — | 10.7 index | measured |
| 2026-10-06 | — | 10.7 index | measured |
| 2026-10-05 | — | 10.7 index | measured |
| 2026-09-09 | — | 10.7 index | measured |
| 2026-08-20 | — | 6.14 index | measured |
| 2026-08-14 | — | 6.14 index | measured |
| 2026-08-13 | — | 6.14 index | measured |
| 2026-07-31 | — | 6.14 index | measured |
| 2026-07-16 | — | 4.78 index | measured |
| 2026-07-15 | — | 11.0 index | measured |
| 2026-06-16 | — | 11.0 index | measured |
| 2026-06-12 | — | 12.1 index | measured |
| 2026-06-04 | — | 12.1 index | measured |
| 2026-06-01 | — | 12.1 index | measured |
| 2026-04-28 | — | 12.1 index | measured |
| 2026-04-24 | — | 12.1 index | measured |
| 2026-04-22 | — | 8.75 index | measured |
| 2026-04-20 | — | 8.75 index | measured |
| 2026-04-14 | — | 9.93 index | measured |
| 2026-04-07 | — | 9.93 index | measured |
| 2026-04-02 | — | 11.7 index | measured |
| 2026-03-18 | — | 11.7 index | measured |
| 2026-02-24 | — | 8.98 index | measured |
| 2026-02-13 | — | 8.98 index | measured |
| 2026-02-12 | — | 8.98 index | measured |
| 2026-02-11 | — | 8.98 index | measured |
| 2026-01-27 | — | 8.43 index | measured |
| 2025-12-22 | — | 10.4 index | measured |
| 2025-12-01 | — | 7.08 index | measured |
| 2025-11-06 | — | 4.79 index | measured |
| 2025-09-30 | — | 5.02 index | measured |
| 2025-09-29 | — | 5.02 index | measured |
| 2025-09-18 | — | 6.22 index | measured |
| 2025-08-21 | — | 6.22 index | measured |
| 2025-08-05 | — | 3.63 index | measured |
| 2025-07-30 | — | 3.63 index | measured |
| 2025-07-29 | — | 3.63 index | measured |
| 2025-07-25 | — | 3.63 index | measured |
| 2025-07-12 | — | 6.24 index | measured |
| 2025-06-20 | — | 6.24 index | measured |
| 2025-06-10 | — | 6.24 index | measured |
| 2025-05-28 | — | 5.59 index | measured |
| 2025-04-29 | — | 7.62 index | measured |
| 2025-04-28 | — | 7.62 index | measured |
| 2025-04-06 | — | 5.20 index | measured |
| 2025-04-05 | — | 5.20 index | measured |
| 2025-03-24 | — | 2.99 index | measured |
| 2025-03-17 | — | 2.99 index | measured |
| 2025-03-12 | — | 2.99 index | measured |
| 2025-03-05 | — | 2.99 index | measured |
| 2025-01-30 | — | 2.99 index | measured |
| 2025-01-20 | — | 2.99 index | measured |
| 2024-12-26 | — | 9.50 index | measured |
| 2024-12-12 | — | 5.08 index | measured |
| 2024-12-06 | — | 6.76 index | measured |
| 2024-11-18 | — | 6.76 index | measured |
| 2024-09-24 | — | 6.76 index | measured |
| 2024-09-19 | — | 6.76 index | measured |
| 2024-09-18 | — | 6.94 index | measured |
| 2024-09-17 | — | 6.94 index | measured |
| 2024-08-30 | — | 1.23 index | measured |
| 2024-07-24 | — | 1.23 index | measured |
| 2024-07-23 | — | 1.23 index | measured |
| 2024-07-18 | — | 4.75 index | measured |
| 2024-06-24 | — | 4.75 index | measured |
| 2024-06-07 | — | 3.74 index | measured |
| 2024-05-27 | — | 4.28 index | measured |
| 2024-05-09 | — | 2.55 index | measured |
| 2024-05-07 | — | 2.55 index | measured |
| 2024-04-23 | — | 4.29 index | measured |
| 2024-04-18 | — | 4.29 index | measured |
| 2024-04-17 | — | 5.28 index | measured |
| 2024-02-22 | — | 8.00 index | measured |
| 2024-02-21 | — | 8.00 index | measured |
| 2024-02-20 | — | 8.00 index | measured |
| 2023-12-12 | — | 7.32 index | measured |
| 2023-12-11 | — | 7.32 index | measured |
| 2023-11-29 | — | 8.41 index | measured |
| 2023-11-22 | — | 8.41 index | measured |
| 2023-11-02 | — | 8.41 index | measured |
| 2023-09-28 | — | 8.74 index | measured |
| 2023-09-27 | — | 8.74 index | measured |
| 2023-09-24 | — | 8.74 index | measured |
| 2023-09-20 | — | 8.74 index | measured |
| 2023-09-11 | — | 8.74 index | measured |
| 2023-09-06 | — | 8.74 index | measured |
| 2023-07-20 | — | 8.74 index | measured |
| 2023-07-18 | — | 12.0 index | measured |
| 2023-06-27 | — | 15.7 index | measured |
| 2023-06-22 | — | 15.7 index | measured |
| 2023-06-01 | — | 15.7 index | measured |
| 2023-05-25 | — | 15.7 index | measured |
| 2023-05-05 | — | 15.7 index | measured |
| 2023-04-24 | — | 15.7 index | measured |
| 2023-04-11 | — | 15.7 index | measured |
| 2023-03-20 | — | 15.7 index | measured |
Why it matters
Open-weight quality converging on the frontier is the single best leading indicator of model-layer commoditisation; a widening gap says the closed labs keep their rents.
What cuts against it
ECI is one composite; open models are often released with a lag that the gap at release date understates; Chinese labs' compute constraints are the confound.
AI Index 2025: the best closed model's lead over the best open one on Chatbot Arena fell from 8.04% in January 2024 to 1.70% in February 2025.
“In early January 2024, the leading closed- weight model outperformed the top open-weight model by 8.04% on the Chatbot Arena Leaderboard. By February 2025, this gap had narrowed to 1.70%.”
How it is measured
- derived metric
open_vs_closed_gap(formula in the semantic layer) - source Epoch AI benchmarks and Capabilities Index · default tier 1 · CC BY 4.0
- proxy benchmark, market_structure · cadence monthly
Four open-weights releases; a move under two ECI points is inside the index's confidence intervals. Widening gap = rents concentrating in the closed labs.
Applied to metric:open_vs_closed_gap.
Derived rows (97)
| as of | dims | value | inputs |
|---|---|---|---|
| 2026-10-17 | 10.2 index | sources12 | |
| 2026-10-15 | 10.7 index | sources123 | |
| 2026-10-06 | 10.7 index | sources123 | |
| 2026-10-05 | 10.7 index | sources123 | |
| 2026-09-09 | 10.7 index | sources123 | |
| 2026-08-20 | 6.14 index | sources123 | |
| 2026-08-14 | 6.14 index | sources123+1 more | |
| 2026-08-13 | 6.14 index | sources123 | |
| 2026-07-31 | 6.14 index | sources123 | |
| 2026-07-16 | 4.78 index | sources12 | |
| 2026-07-15 | 11.0 index | sources123+1 more | |
| 2026-06-16 | 11.0 index | sources12 | |
| 2026-06-12 | 12.1 index | sources123 | |
| 2026-06-04 | 12.1 index | sources123 | |
| 2026-06-01 | 12.1 index | sources123 | |
| 2026-04-28 | 12.1 index | sources123 | |
| 2026-04-24 | 12.1 index | sources123+1 more | |
| 2026-04-22 | 8.75 index | sources123 | |
| 2026-04-20 | 8.75 index | sources12 | |
| 2026-04-14 | 9.93 index | sources123 | |
| 2026-04-07 | 9.93 index | sources12 | |
| 2026-04-02 | 11.7 index | sources123+1 more | |
| 2026-03-18 | 11.7 index | sources123 | |
| 2026-02-24 | 8.98 index | sources123+1 more | |
| 2026-02-13 | 8.98 index | sources123 | |
| 2026-02-12 | 8.98 index | sources123 | |
| 2026-02-11 | 8.98 index | sources123 | |
| 2026-01-27 | 8.43 index | sources12 | |
| 2025-12-22 | 10.4 index | sources123 | |
| 2025-12-01 | 7.08 index | sources12 | |
| 2025-11-06 | 4.79 index | sources12 | |
| 2025-09-30 | 5.02 index | sources123 | |
| 2025-09-29 | 5.02 index | sources12 | |
| 2025-09-18 | 6.22 index | sources123 | |
| 2025-08-21 | 6.22 index | sources123 | |
| 2025-08-05 | 3.63 index | sources123+1 more | |
| 2025-07-30 | 3.63 index | sources123 | |
| 2025-07-29 | 3.63 index | sources123 | |
| 2025-07-25 | 3.63 index | sources123 | |
| 2025-07-12 | 6.24 index | sources123 | |
| 2025-06-20 | 6.24 index | sources123 | |
| 2025-06-10 | 6.24 index | sources123 | |
| 2025-05-28 | 5.59 index | sources12 | |
| 2025-04-29 | 7.62 index | sources123+2 more | |
| 2025-04-28 | 7.62 index | sources123 | |
| 2025-04-06 | 5.20 index | sources123 | |
| 2025-04-05 | 5.20 index | sources123 | |
| 2025-03-24 | 2.99 index | sources123 | |
| 2025-03-17 | 2.99 index | sources123 | |
| 2025-03-12 | 2.99 index | sources123+2 more | |
| 2025-03-05 | 2.99 index | sources123 | |
| 2025-01-30 | 2.99 index | sources123 | |
| 2025-01-20 | 2.99 index | sources123+1 more | |
| 2024-12-26 | 9.50 index | sources12 | |
| 2024-12-12 | 5.08 index | sources12 | |
| 2024-12-06 | 6.76 index | sources123 | |
| 2024-11-18 | 6.76 index | sources123 | |
| 2024-09-24 | 6.76 index | sources123+1 more | |
| 2024-09-19 | 6.76 index | sources123 | |
| 2024-09-18 | 6.94 index | sources123+2 more | |
| 2024-09-17 | 6.94 index | sources123 | |
| 2024-08-30 | 1.23 index | sources123 | |
| 2024-07-24 | 1.23 index | sources123 | |
| 2024-07-23 | 1.23 index | sources123+1 more | |
| 2024-07-18 | 4.75 index | sources123 | |
| 2024-06-24 | 4.75 index | sources123+1 more | |
| 2024-06-07 | 3.74 index | sources12 | |
| 2024-05-27 | 4.28 index | sources123 | |
| 2024-05-09 | 2.55 index | sources123 | |
| 2024-05-07 | 2.55 index | sources12 | |
| 2024-04-23 | 4.29 index | sources123+2 more | |
| 2024-04-18 | 4.29 index | sources123 | |
| 2024-04-17 | 5.28 index | sources12 | |
| 2024-02-22 | 8.00 index | sources123 | |
| 2024-02-21 | 8.00 index | sources123+1 more | |
| 2024-02-20 | 8.00 index | sources123+1 more | |
| 2023-12-12 | 7.32 index | sources123 | |
| 2023-12-11 | 7.32 index | sources12 | |
| 2023-11-29 | 8.41 index | sources123 | |
| 2023-11-22 | 8.41 index | sources123 | |
| 2023-11-02 | 8.41 index | sources123+2 more | |
| 2023-09-28 | 8.74 index | sources123 | |
| 2023-09-27 | 8.74 index | sources123 | |
| 2023-09-24 | 8.74 index | sources123 | |
| 2023-09-20 | 8.74 index | sources123 | |
| 2023-09-11 | 8.74 index | sources123 | |
| 2023-09-06 | 8.74 index | sources123+1 more | |
| 2023-07-20 | 8.74 index | sources12 | |
| 2023-07-18 | 12.0 index | sources123+1 more | |
| 2023-06-27 | 15.7 index | sources123 | |
| 2023-06-22 | 15.7 index | sources123 | |
| 2023-06-01 | 15.7 index | sources123 | |
| 2023-05-25 | 15.7 index | sources123 | |
| 2023-05-05 | 15.7 index | sources123 | |
| 2023-04-24 | 15.7 index | sources123 | |
| 2023-04-11 | 15.7 index | sources123 | |
| 2023-03-20 | 15.7 index | sources123 |
Latest readings
- 2026-10-17 · 10.2 indexas of 2026-10-17(2 obs)
- 2026-10-15 · 10.7 indexas of 2026-10-15(3 obs)
- 2026-10-06 · 10.7 indexas of 2026-10-06(3 obs)
- 2026-10-05 · 10.7 indexas of 2026-10-05(3 obs)
- 2026-09-09 · 10.7 indexas of 2026-09-09(3 obs)
- 2026-08-20 · 6.14 indexas of 2026-08-20(3 obs)
Why this status, and its history
The gap fell from 11.5 to 5.8 ECI points with one open-weights release on 16 Jul 2026, then held flat across three more releases. One move in four readings is not a trend under the direction rule, so the reading moves from dispersing to unclear. The earlier reading counted flat steps as agreeing with a fall, an evaluator bug fixed in this change.
- 2026-09-11dispersing to unclearconf 55 → 55 · Claude (model)
The gap fell from 11.5 to 5.8 ECI points with one open-weights release on 16 Jul 2026, then held flat across three more releases. One move in four readings is not a trend under the direction rule, so the reading moves from dispersing to unclear. The earlier reading counted flat steps as agreeing with a fall, an evaluator bug fixed in this change.
sources123 - 2026-09-10unmeasured to dispersingconf — → 55 · the evaluator (automatic)
Evaluator: 5.77 (Epoch AI benchmarks and Capabilities Index, 2026-08-20) reads dispersing over 4 periods with a dead band of 2. Auto-reason; rule rationale: Four open-weights releases; a move under two ECI points is inside the index's confidence intervals. Widening gap = rents concentrating in the closed labs.
sources123
Why this confidence
Rests on 149 observations from Epoch AI benchmarks and Capabilities Index; best evidence tier 1, grade A; current.
Confidence is independent of status: 90–95 multiple strong independent sources; 70–89 good evidence, some ambiguity; 50–69 mixed or hard to operationalise; 0–49 limited or vague evidence.
Predictions that lean on this
- Too early to tell
- Too early to tell