Automatic Identification and Classification of Share Buybacks and their Effect on Short-, Mid- and Long-Term Returns

TL;DR

This thesis develops NLP methods to detect share buyback announcements, analyzes their impact on stock returns, and trains machine learning models to predict excess returns with high accuracy, revealing strategic insights for investors.

Contribution

It introduces two NLP approaches for automated detection of buyback announcements and demonstrates their effectiveness with small data, creating a large dataset for detailed analysis.

Findings

Companies with large buyback volumes outperform the market.

Buybacks during crises lead to better market performance.

Machine learning models achieve up to 77% accuracy in return prediction.

Abstract

This thesis investigates share buybacks, specifically share buyback announcements. It addresses how to recognize such announcements, the excess return of share buybacks, and the prediction of returns after a share buyback announcement. We illustrate two NLP approaches for the automated detection of share buyback announcements. Even with very small amounts of training data, we can achieve an accuracy of up to 90%. This thesis utilizes these NLP methods to generate a large dataset consisting of 57,155 share buyback announcements. By analyzing this dataset, this thesis aims to show that most companies, which have a share buyback announced are underperforming the MSCI World. A minority of companies, however, significantly outperform the MSCI World. This significant overperformance leads to a net gain when looking at the averages of all companies. If the benchmark index is adjusted for the respective size of the companies, the average overperformance disappears, and the majority underperforms even greater. However, it was found that companies that announce a share buyback with a volume of at least 1% of their market cap, deliver, on average, a significant overperformance, even when using an adjusted benchmark. It was also found that companies that announce share buybacks in times of crisis emerge better than the overall market. Additionally, the generated dataset was used to train 72 machine learning models. Through this, it was able to find many strategies that could achieve an accuracy of up to 77% and generate great excess returns. A variety of performance indicators could be improved across six different time frames and a significant overperformance was identified. This was achieved by training several models for different tasks and time frames as well as combining these different models, generating significant improvement by fusing weak learners, in order to create one strong learner.