Georgios Papaioannou

Author directory

2026

Natural language processing (NLP) has been widely used in quantitative finance, but traditional methods often struggle to capture rich narratives in textual data, leaving potentially informative signals under-explored. Large language models (LLMs) offer a promising alternative as they are able to extract nuanced semantics. In this paper, we ask whether semantic signals extracted by LLMs from corporate disclosures predict abnormal returns (alpha) beyond broad market movements and common risk factors. We introduce a simple framework, *LLM as extractor, embedding as ruler*, which extracts context-aware, metric-focused textual spans and quantifies semantic changes across consecutive disclosure periods using embedding similarity. This allows us to measure the degree of metric shifting - how much firms move away from previously emphasized metrics, referred to as moving targets. In portfolio and cross-sectional regression tests against a recent traditional baseline, our method yields a moving-targets signal that delivers significant risk-adjusted alpha. Qualitative analysis suggests that these gains stem from preserving contextual qualifiers and filtering out non-metric terms that traditional approaches often miss.

2022

Today classicists are provided with a great number of digital tools which, in turn, offer possibilities for further study and new research goals. In this paper we explore the idea that old Greek handwriting can be machine-readable and consequently, researchers can study the target material fast and efficiently. Previous studies have shown that Handwritten Text Recognition (HTR) models are capable of attaining high accuracy rates. However, achieving high accuracy HTR results for Greek manuscripts is still considered to be a major challenge. The overall aim of this paper is to assess HTR for old Greek manuscripts. To address this statement, we study and use digitized images of the Oxford University Bodleian Library Greek manuscripts. By manually transcribing 77 images, we created and present here a new dataset for Handwritten Paleographic Greek Text Recognition. The dataset instances were organized by establishing as a leading factor the century to which the manuscript and hence the image belongs. Experimenting then with an HTR model we show that the error rate depends on the century of the image.