Short Sale Bans and their Impact on the Microstructure of Equity Markets

Table of Contents

1 Introduction

2 Short Selling (Bans)

2.1 The Idea of Short Selling

2.2 Evolution of Short Selling (Bans)

2.3 European Short Sale Bans in 2020

3 Literature Overview

4 Stock Liquidity

4.1 Variables and Data

4.2 Methodology

4.3 Empirical Results

4.4 Robustness Check

4.5 Effects of the Ban Lift

4.6 Country-by-Country Analysis

5 Price Efficiency

6 Stock Prices

7 Conclusion

Research Objectives and Topics

This master's thesis examines the impact of short sale bans imposed during the Covid-19 crisis in spring 2020 on the market microstructure of European equity markets, specifically evaluating effects on liquidity, price efficiency, and stock price stabilization.

• Analysis of market liquidity degradation for large firms during short sale bans.
• Evaluation of price efficiency reduction using price delay measures.
• Investigation into whether short sale bans achieve the regulatory goal of stock price stabilization.
• Empirical verification of market reactions following the lifting of short sale bans.
• Comparison of banned versus non-banned stocks across 28 European countries.

Excerpt from the Book

Summary of Chapters

1 Introduction: This chapter outlines the market context of the 2020 Covid-19 crisis and defines the thesis's focus on the impact of short sale bans on market microstructure.

2 Short Selling (Bans): This chapter provides the theoretical framework of short selling mechanics and reviews the historical development and specific implementation of 2020 European bans.

3 Literature Overview: This section reviews existing academic literature regarding the effects of short sale bans on market liquidity, price efficiency, and stock prices.

4 Stock Liquidity: This chapter empirically analyzes how short sale bans influence market liquidity using various proxies and provides robustness checks through matching procedures.

5 Price Efficiency: This section tests whether short sale bans reduce price efficiency by examining how slowly stock prices incorporate idiosyncratic and market-wide information.

6 Stock Prices: This chapter investigates whether short sale bans effectively stabilize stock prices and prevent them from being artificially pushed downwards.

7 Conclusion: The final chapter summarizes the empirical findings and discusses the implications for regulatory policy regarding short sale restrictions.

Keywords

Short Sale Bans, Market Microstructure, Stock Liquidity, Price Efficiency, Covid-19, European Equity Markets, Bid-Ask Spread, Amihud Ratio, Dollar Trading Volume, Abnormal Returns, Market Stabilization, Financial Regulation, Diff-in-Diff Estimation, Stock Price Volatility, Capital Markets

Frequently Asked Questions

What is the fundamental topic of this thesis?

This thesis examines the consequences of temporary short sale bans introduced by several European countries during the market volatility triggered by the 2020 Covid-19 pandemic.

What are the central themes of the research?

The core themes include the impact on market liquidity, the speed of price discovery (price efficiency), and the regulatory objective of stabilizing stock prices during market downturns.

What is the primary research goal?

The primary goal is to empirically determine if short sale bans achieve their intended regulatory purpose or if they lead to negative side effects such as impaired market quality.

Which scientific methodology is applied?

The author employs a difference-in-differences (diff-in-diff) empirical approach using panel regression models, controlling for firm characteristics and market-wide developments, alongside matching procedures for robustness.

What does the main body cover?

The main body systematically analyzes liquidity proxies, tests price efficiency models, and performs abnormal return analyses to evaluate whether banned stocks exhibit different performance compared to non-banned control stocks.

Which keywords define this work?

Key terms include short sale bans, market microstructure, stock liquidity, price efficiency, and European equity markets.

How does the author define market liquidity in this study?

The author primarily measures liquidity through the percentage bid-ask spread, the Amihud illiquidity ratio, and dollar trading volume to capture different dimensions of liquidity and market turnover.

Does the thesis find that short sale bans successfully stabilize stock prices?

No, the empirical findings suggest that the bans do not prevent stock price declines or artificially push prices upwards, indicating that the intended stabilization goal is not met.

What happens to market liquidity when the bans are lifted?

The study finds that liquidity tends to rebound or improve after the bans are lifted, suggesting a reversal of the negative liquidity effects observed during the ban period.