A Review of Large Language Models for Stock Price Forecasting from a Hedge-Fund Perspective

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A Review of Large Language Models for Stock Price Forecasting from a Hedge-Fund Perspective

Olivia Zhang
Zhilin Zhang
Published on 4/10/2026
Equities
Stocks
AI
LLM
Sentiment
Machine learning
Stock picking
Event Driven
Multi-Agent

This review synthesizes recent applications of large language models (LLMs) for stock price forecasting from a hedge-fund perspective, covering sentiment extraction, financial report analysis, price series tokenization, and multi-agent trading systems. It critically evaluates practical pitfalls often understated in academic literature, including fragility in sentiment analysis due to context dependence and regime shifts, short evaluation horizons that fail to span full market cycles, misalignment of evaluation metrics (e.g., MSE, accuracy) with real-world trading objectives (e.g., risk-adjusted returns), data leakage from cross-day event drift and literal label statements, and the impact of illiquidity premiums on strategy feasibility. The review also discusses the limits of stock price predictability, suggesting that markets alternate between random-walk and predictable regimes, and advocates for regime-switch detection. Practical guidelines are provided for deploying LLMs in production-grade trading pipelines, such as using long-horizon datasets, risk-adjusted metrics, rigorous leakage controls, and benchmarking against non-LLM baselines. The paper highlights the gap between academic prototypes and real-world trading systems, emphasizing the need for robustness under realistic market frictions.

Highlights

  • 1Provides a hedge-fund perspective on LLM-based stock price forecasting, emphasizing practical pitfalls often overlooked in academic literature.
  • 2Reviews four key application areas: sentiment analysis, financial report analysis, price series tokenization, and multi-agent trading systems.
  • 3Critically assesses issues such as sentiment fragility, dataset horizon limitations, performance metric misalignment, data leakage, illiquidity premiums, and stock price predictability.
  • 4Offers practical guidelines for deploying LLMs in real-world trading pipelines, including regime-spanning datasets, risk-adjusted metrics, and rigorous leakage controls.

Methods

  • M
    Sentiment extraction from news and social media using LLMs (e.g., GPT-4, FinBERT) with prompt engineering and fine-tuning.
  • M
    Tokenization/symbolization of stock price series into discrete tokens for next-token prediction with LLMs.
  • M
    Multi-agent LLM architectures (e.g., Mixture-of-Experts, role-based agents) for collaborative decision-making in trading.
  • M
    Retrieval-Augmented Generation (RAG) and reasoning frameworks (ReACT, Chain-of-Thought, Tree-of-Thought, Reflexion) for agentic trading systems.

Results

  • R
    Sentiment-only signals often yield hit rates marginally above chance and are context-dependent, with sign reversals across market regimes.
  • R
    Tokenization-based LLMs can achieve high returns (e.g., 119% annual return, Sharpe ratio 6.5) but are sensitive to binning design and model-specific hyperparameters.
  • R
    Multi-agent systems reduce hallucinations and overfitting by fusing diverse specialist perspectives, but rely heavily on data quality.
  • R
    Many studies evaluate over short horizons (e.g., 1-2 years), failing to cover full market cycles, leading to regime-specific and potentially non-robust results.
  • R
    Illiquidity premiums (e.g., 10 bps daily) can materially erode cumulative returns, turning profitable strategies unprofitable after accounting for transaction costs.
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