Ai4
Fine-tuning open-source language models on hierarchical annotations beats GPT-4 and achieves a 1.04 Information Ratio by shorting equities following high-confidence negative ESG controversies.
AI-assisted summary of Presentation by Che Guan, Alliance Bernstein — original source. Check the original for full context.
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## Background Published on YouTube by the Ai4 channel on August 19, 2026, this video features Che Guan, Principal Data Scientist at AllianceBernstein, presenting research on extracting ESG insights from news data. The session outlines how fine-tuning open-source LLMs on expert-annotated datasets outperforms off-the-shelf models to produce tradeable sentiment signals and enhance quantitative alpha generation.
## TL;DR Guan demonstrates that zero-shot LLM prompting is highly fragile for complex financial tasks and presents a structured three-stage hierarchical annotation framework based on SASB standards. Fine-tuning open-source models like Llama 3 8B on this expert dataset enabled the team to achieve 77% accuracy, surpassing general-purpose models like GPT-4. Quantitative event studies and backtests across S&P 500 stocks showed that negative ESG news consistently predicted underperformance, with a shorting strategy on high-confidence negative sentiment yielding over 25% annual excess return and an Information Ratio of 1.04. Finally, Guan outlines upcoming work utilizing reinforcement learning to dynamically align sentiment signals across varying holding horizons.
## Atmosphere & style The presentation strikes a polished, pragmatic, and highly analytical tone, opening with a self-aware joke about standing between the audience and their lunch. Guan delivers a lucid, empirical breakdown that strips away generative AI hype, grounding his arguments in interactive audience polling and striking benchmarks on prompt sensitivity. It feels like an authoritative quantitative finance masterclass—engaging, transparent about model pitfalls, and focused squarely on disciplined, real-world alpha extraction.
## Key takeaways - [02:20](https://www.youtube.com/watch?v=A1FLWhmEJeM&t=140s) Zero-shot prompting in off-the-shelf LLMs is too brittle for mission-critical quantitative finance, as minor whitespace or formatting changes can cause classification accuracy to swing dramatically. - [02:20](https://www.youtube.com/watch?v=A1FLWhmEJeM&t=140s) Accurate financial NLP requires a structured three-step sequential pipeline: identifying SASB ESG topic relevance, establishing direct firm impact, and determining directional sentiment. - [06:23](https://www.youtube.com/watch?v=A1FLWhmEJeM&t=383s) The study utilized a foundational dataset of 120,000 Perigon news articles across 508 S&P 500 companies (214,000 entity-article pairs), with 5,250 articles labeled by SASB-trained human annotators. - [13:40](https://www.youtube.com/watch?v=A1FLWhmEJeM&t=820s) ESG news exhibits a structural asymmetry where negative events outnumber positive events roughly 2-to-1, because positive announcements are often generic PR while negative news covers concrete controversies. - [13:40](https://www.youtube.com/watch?v=A1FLWhmEJeM&t=820s) Fine-tuning open-source models like Llama 3 8B Instruct on domain-specific expert annotations achieves 77% accuracy, outperforming larger proprietary models including GPT-4. - [16:46](https://www.youtube.com/watch?v=A1FLWhmEJeM&t=1006s) Event study analysis shows that negative ESG news predicts statistically significant next-day excess underperformance of -5 basis points, widening to -8 basis points for high-confidence negative news. - [16:46](https://www.youtube.com/watch?v=A1FLWhmEJeM&t=1006s) A 1-year backtest shorting companies in the extreme negative ESG cohort generated over 25% cumulative excess return relative to the S&P 500 benchmark. - [16:46](https://www.youtube.com/watch?v=A1FLWhmEJeM&t=1006s) The high-confidence negative ESG sentiment strategy achieved an Information Ratio of 1.04, well above the quantitative investment benchmark of 0.50 for standalone alpha signals. - [22:41](https://www.youtube.com/watch?v=A1FLWhmEJeM&t=1361s) Human sentiment annotations suffer from temporal decay, where signals that generate positive next-day alpha can completely dissipate over a 3-month holding period. - [22:41](https://www.youtube.com/watch?v=A1FLWhmEJeM&t=1361s) Reinforcement Learning with forward investment returns as reward functions can dynamically align sentiment model outputs to specific multi-horizon investment strategies.
## Detailed walkthrough ### [00:04](https://www.youtube.com/watch?v=A1FLWhmEJeM&t=4s) Introduction and the Nuance of ESG News Sentiment
Che Guan opens his presentation by acknowledging the palpable tension in the room: "I have a pressure because I know that I'm speaking between you and lunch. So I try to finish my presentation on time so that you don't have to stay in the long line." He frames his talk around optimizing Large Language Models (LLMs) for sustainable investing, emphasizing that while the underlying architectures are straightforward, the practical insights can directly enhance investment strategies. The research represents a collaborative effort between Che Guan, his colleague Andrew Chen at AllianceBernstein, and three students from the Data Science Institute at Vanderbilt University.
To demonstrate why off-the-shelf LLM sentiment analysis often fails in finance, Guan conducts an interactive experiment with the audience. Presenting a real-world news article from July 13, 2023, referencing insurance companies Liberty Mutual and Allstate, he polls the room on whether the headline tone is positive, negative, or neutral. While the audience offers mixed answers, Gemini evaluates both instances as negative.
[02:20](https://www.youtube.com/watch?v=A1FLWhmEJeM&t=140s) Prompt Fragility and Nested Sentiment Logic
Guan demonstrates the fragility of naive LLM reasoning by introducing a minor synthetic modification to the text: appending a line mentioning "Company XYZ". When asked whether the article impacts Company XYZ from an Environmental, Social, and Governance (ESG) perspective, Gemini misclassifies it as positive. In reality, the correct classification is neutral because merely mentioning an entity in a boilerplate sign-off does not mean the underlying ESG event affects that firm.
As Guan explains, real-world financial NLP involves deeply nested dependencies: first, determining whether an article covers a relevant ESG topic; second, establishing whether that topic directly impacts the specific company; and third, evaluating the sentiment tone of that specific impact. While prompt engineering attempts to guide models through these nuances, Guan illustrates how dangerously brittle zero-shot prompting can be by referencing empirical findings on Llama 2. In a four-way classification benchmark across demographic and professional categories:
- Formatting the prompt as `Passage: <text>\nAnswer: <class>` yielded an accuracy of roughly **0.0036** (0.36%). - Replacing the colon with a space (`Passage <text>\nAnswer <class>`) caused accuracy to jump to **0.50** (50%). - Inserting a single space after the colon (`Passage: <text>\nAnswer: <class>`) boosted performance to **0.75** (75%).
This extreme sensitivity demonstrates that prompting alone is not robust enough for mission-critical quantitative investment pipelines.
```mermaid flowchart TD accTitle: Three-Step Sequential ESG Annotation Pipeline subgraph S1["Step 1: ESG Topic Relevance"] A["Raw News Article"] --> B{"Focus on SASB ESG Topics?"} B -- "Primary Focus" --> C1["Major ESG"] B -- "Secondary Focus" --> C2["Minor ESG"] B -- "No ESG Content" --> C3["No ESG / Irrelevant"] end
subgraph S2["Step 2: Firm Impact"] C1 & C2 --> D{"Direct Impact on Target Company?"} D -- "Core Operational Impact" --> E1["Major Impact"] D -- "Peripheral Impact" --> E2["Minor Impact"] D -- "Incidental Mention" --> E3["No Firm Impact"] C3 --> E4["Irrelevant"] end
subgraph S3["Step 3: Sentiment & Tone"] E1 & E2 --> F{"Evaluate Tone of Impact"} F --> G1["Positive Tone"] F --> G2["Neutral Tone"] F --> G3["Negative Tone"] E3 & E4 --> G4["Irrelevant"] end ```
[06:23](https://www.youtube.com/watch?v=A1FLWhmEJeM&t=383s) Research Scope and the Perigon News Dataset
To overcome prompting instability, Guan outlines the four core contributions of the project: creating a high-quality expert-annotated ESG dataset, fine-tuning open-source LLMs across ESG dimensions, evaluating model performance against leading proprietary benchmarks, and running quantitative backtests on S&P 500 equities.
The foundational dataset originates from the Perigon news stream, comprising 120,000 news articles published between September 2022 and September 2023. The corpus covers 508 companies in the S&P 500. Because individual articles frequently mention multiple firms, the team capped company associations at five entities per article, yielding an expanded universe of 214,000 sample-pair evaluations.
- Roughly 200 companies in the universe had fewer than 50 articles written about them across the full year. - Approximately 100 heavily covered companies had around 250 articles per year, representing roughly one dedicated article per trading day. - Human annotators were trained using the Sustainability Accounting Standards Board (SASB) framework across five core dimensions: Environment, Social Capital, Human Capital, Business Model & Innovation, and Leadership & Governance.
[09:23](https://www.youtube.com/watch?v=A1FLWhmEJeM&t=563s) Sequential Annotation and ESG Signal Construction
To ensure consistent data labeling across 79 distinct industries, the team randomly sampled 5,250 articles and implemented a three-stage hierarchical annotation workflow. Rather than evaluating sentiment in a single pass, annotators systematically answered three dependent questions:
1. **ESG Relevance (Table 1):** Is the article substantially focused on SASB ESG themes? (Categorized as *Major*, *Minor*, or *No*). 2. **Firm Impact (Table 2):** If ESG-relevant, does the news meaningfully affect the company under review? (Categorized as *Major*, *Minor*, *No*, or *Irrelevant* if step 1 was *No*). 3. **Sentiment Polarity (Table 3):** If both ESG and firm relevance are present, what is the directional tone? (Categorized as *Positive*, *Negative*, or *Neutral*; otherwise marked *Irrelevant*).
From these granular labels, Guan's team constructed two distinct trading signals:
- **All ESG News with Firm Impact (Broader Signal):** Requires ESG relevance to be *Major* or *Minor*, and firm impact to be *Major* or *Minor*. Polarity follows the tone (Positive, Negative, Neutral); all other combinations become *Irrelevant*. - **Core ESG News with Firm Impact (Strict Signal):** Imposes tighter constraints, requiring both ESG relevance and firm impact to be strictly *Major* alongside the respective sentiment polarity.
[13:40](https://www.youtube.com/watch?v=A1FLWhmEJeM&t=820s) Label Asymmetry and LLM Fine-Tuning Performance
Analyzing the annotated distributions reveals a pronounced structural skew: negative news heavily outnumbers positive news. In the broader signal, the split stands at 69% neutral, 15% negative, 8% positive, and 8% irrelevant. In the strict core signal, 84% are irrelevant, 9% are negative, and only 4% are positive. Across both definitions, negative instances appear at double the volume of positive instances. Guan explains that positive corporate announcements tend to be generic PR boilerplate, whereas negative ESG events describe concrete, tangible controversies that annotators and models can classify with high confidence.
| Model Category | Model Name | Fine-Tuning Setup | Key Outcome / F1 & Accuracy | |:--- |:--- |:--- |:--- | | **Open Source** | Mistral 7B (Base & Instruct) | Pre-trained vs. Fine-tuned | Fine-tuning substantially improves macro F1 | | **Open Source** | Llama 3 8B (Base & Instruct) | Pre-trained vs. Fine-tuned | Fine-tuned Instruct achieves peak **77% overall accuracy** | | **Closed Source** | GPT-3.5 Turbo, GPT-4o mini, GPT-4 | Zero/Few-shot Inference | Outperformed by fine-tuned 8B parameter models |
Guan notes that fine-tuning an open-source 8B parameter model on domain-specific human annotations enables it to surpass general-purpose proprietary giants like GPT-4, delivering both superior accuracy and reproducible sentiment scores.
[16:46](https://www.youtube.com/watch?v=A1FLWhmEJeM&t=1006s) Event Studies, Aggregation, and Backtest Alpha
Using the fine-tuned Llama 3 8B Instruct model, the team scored the entire 214,000-article corpus. They established an event study framework to trade the stock the day following publication and close the position on the subsequent day, measuring 1-day forward excess returns relative to the S&P 500 benchmark. The data was segmented into five cohorts: *ESG-relevant*, *Positive*, *Neutral*, *Negative*, and an *Extreme Negative* subset where the model exhibited high classification confidence.
- **Article-Level Excess Returns:** Negative news generated average 1-day excess returns of **-5 basis points per day**, while the extreme negative cohort produced **-8 basis points per day** with statistically significant t-statistic p-values. - **Company-Level Daily Aggregation:** Because firms frequently receive multiple news hits daily, signals were aggregated into a single daily company sentiment score using majority voting. - **1-Year Cumulative Backtest Performance:** Starting with an initial capital of $1, an investor shorting the extreme negative cohort generated over **25% excess returns** across the one-year evaluation period. - **Risk-Adjusted Performance:** The Information Ratio (IR) reached **0.65** for the standard negative cohort and climbed to **1.04** for the extreme negative cohort (far exceeding the standard 0.50 threshold used by quantitative managers to define an attractive standalone trading signal).
[22:41](https://www.youtube.com/watch?v=A1FLWhmEJeM&t=1361s) Future Work: Horizon Alignment via Reinforcement Learning
In concluding the presentation, Guan addresses a fundamental limitation of static human annotations: temporal decay. When investment horizons shift from next-day execution to one-month or three-month holdings, human-assigned sentiment labels can lose predictive power or flip entirely.
Guan illustrates this challenge using ExxonMobil's March 10, 2026 announcement regarding the relocation of its corporate headquarters to Texas:
- **Next-Day Performance:** Stock surged by **+2%**. - **1-Month Performance:** Cumulative gain expanded to **+7%**. - **3-Month Horizon:** Excess returns completely dissipated back to neutral benchmark performance.
A human label of "Positive" is valid for short-term alpha, but misleading for a multi-month allocator. To solve this, Guan previews upcoming research applying Reinforcement Learning (RL) to dynamically align sentiment distributions with specific investment horizons. By utilizing multi-month forward returns as the RL reward function, the model is penalized when a short-term positive signal fades, dynamically recalibrating its output toward neutral for longer-term strategies. Guan concludes by promising to share the empirical RL alignment results in the following year's presentation.
## Notable quotes > [00:04](https://www.youtube.com/watch?v=A1FLWhmEJeM&t=4s) I have a pressure because I know that I'm speaking between you and lunch. So I try to finish my presentation on time so that you don't have to stay in the long line. — Che Guan
> [02:20](https://www.youtube.com/watch?v=A1FLWhmEJeM&t=140s) Passage: <text> Answer: <class>
> [02:20](https://www.youtube.com/watch?v=A1FLWhmEJeM&t=140s) Passage <text> Answer <class>
> [02:20](https://www.youtube.com/watch?v=A1FLWhmEJeM&t=140s) Passage: <text> Answer: <class>
## Mentioned AllianceBernstein, Allstate, Andrew Chen, Che Guan, Data Science Institute at Vanderbilt University, ExxonMobil, Gemini, GPT-3.5 Turbo, GPT-4, GPT-4o mini, Liberty Mutual, Llama 2, Llama 3 8B, Llama 3 8B Instruct, Mistral 7B, Perigon, S&P 500, SASB
## Video description Che Guan - Principal Data Scientist, AllianceBernstein
We use Large Language Models (LLMs) and Natural Language Processing (NLP) to extract Environmental, Social and Governance (ESG) insights from real-time news, creating an expert-annotated dataset to evaluate ESG classification, firm relevance, and sentiment. Our fine-tuned models outperform pre-trained ones in ESG detection, firm impact, and sentiment analysis. Furthermore, in-context learning does not improve performance, indicating optimal tuning. Event studies and backtests show that our sentiment signals predict underperforming stocks, with higher model confidence in negative sentiment correlating to worse outcomes. These findings emphasize the value of fine-tuning models with expert-annotated data, and leveraging ESG sentiment signals to generate investment insights from qualitative data to enhance alpha generation.
[Source](https://www.youtube.com/watch?v=A1FLWhmEJeM)