arXiv Machine Learning
Aug 19

Temporal Leakage in Financial News NLP: A Multi-Architecture Audit with a Regime-Specific M&A Signal

The paper audits the impact of temporal leakage on financial-news direction prediction across 49,799 articles and 16 feature-model combinations, including TF‑IDF, MiniLM, FinBERT, and fine‑tuned RoBERTa‑large / DeBERTa‑v3‑large, as well as zero/few‑shot and LoRA probes of Llama‑3 and Qwen2.5. Random train‑test splits inflate MCC scores by 1.1× to 6.5×, with larger models and richer features showing greater gains, while end‑to‑end FinBERT fine‑tuning actually increases the gap. Only the mergers and acquisitions (M&A) category shows a positive locked‑test signal under near‑temporal chronological evaluation, with the signal localized to 2024‑2025 European‑tilted M&A semantics and not transferring to a 2009‑2020 U.S. corpus.

By Chenhao Xue, Raslen Guesmi, Siwei Feng, Yucheng Gong, Jacob Xavier Sundram, Jordan Pang, Lan Wang, Julian Kaljuvee
arXiv AI
Sep 3

Dutch Books for Language Models

The paper investigates the coherence of probabilistic forecasts produced by language models, particularly in the context of life‑decision support. Using a de Finetti‑based method, the authors elicit forecasts for events derived from stock return data and compute the maximum Dutch‑book profit via linear programming, which quantifies incoherence. They find significant incoherence, especially when events have complex logical relationships or when irrelevant context is present, and suggest that alternative training strategies could improve coherence.

By Isaiah Andrews, Suproteem Sarkar
arXiv AI
3d ago

Understanding as No-Arbitrage: Bounded Dutch Books as a Definition and Training Objective for Language Models

The paper proposes measuring a language model’s understanding via no‑arbitrage, defining it as the inability of a bounded trader to profit from Dutch books against the model’s probabilities on logically related claims. It shows that full logical coherence is computationally infeasible, that standard next‑token training yields incoherent predictions across formats, and that uncertainty grows predictably along reasoning chains, creating arbitrage opportunities. The authors introduce Arbitr, a training framework that penalizes logical inconsistencies while maintaining accuracy, reducing exploitability by orders of magnitude and revealing a scaling illusion where large models appear coherent yet exhibit extreme unjustified confidence.

By Daniel Dragonevskiy