Impact of Antitrust Events on Firm Market Value: Evidence from Chinese and US Internet Platforms

Yong Huang; Nina Yin; Vanessa Yanhua Zhang; Shan Zhao

doi:10.1007/s11151-025-10035-z

Impact of Antitrust Events on Firm Market Value: Evidence from Chinese and US Internet Platforms

Yong Huang, Nina Yin^*, Vanessa Yanhua Zhang^*, Shan Zhao

^*Corresponding author for this work

Department of Economics and Finance

Research output: Journal Publications and Reviews › RGC 21 - Publication in refereed journal › peer-review

1 Citation (Scopus)

Abstract

This study compares the effect of antitrust regulations on firm market value for Chinese versus U.S. internet platforms. Applying an event study approach to daily stock market data during 2010-2022, we investigate the cumulative abnormal returns of Hong Kong- and U.S.-listed internet platforms. We find that the launch of an antitrust investigation in China causes a significant decrease in the investigated firm's market value but boosts the market value of its competitors; while the end of the investigation increases the investigated firm's market value but dampens the market value of other leading platforms that involve the alleged exclusive dealing conduct. A similar analysis on U.S. internet platforms shows minor effects of EU/U.S. antitrust regulations and actions. These results indicate that differences in enforcement duration and uncertainty of antitrust enforcement matter. Stronger stock market reactions to Chinese versus EU/U.S. antitrust legislation are also observed, which suggests investors' belief in the Chinese antitrust authority's stronger discretion in antitrust enforcement.

© The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature
2025, Corrected publication 2025

Original language	English
Pages (from-to)	251-288
Number of pages	38
Journal	Review of Industrial Organization
Volume	67
Issue number	3
Online published	13 Oct 2025
DOIs	https://doi.org/10.1007/s11151-025-10035-z
Publication status	Published - Oct 2025

Funding

The work described in this paper was partially supported by Program for Innovation Research in Central University of Finance and Economics (Project No. 026050323001) and partially supported by a grant from City University of Hong Kong (Project No. 7005469). The authors have no relevant financial or non-financial interests to disclose.

Research Keywords

Administrative enforcement
Antitrust regulation
Event study
Internet platform
Judicial remedies
Market value
L41
L44
G14
G11

Access Output

10.1007/s11151-025-10035-z

Other Access Options

Check CityUHK Library

Permanent Link

Right click to copy link

Cite this

@article{1d5bf18f705e42728a2375e04691682a,

title = "Impact of Antitrust Events on Firm Market Value: Evidence from Chinese and US Internet Platforms",

abstract = "This study compares the effect of antitrust regulations on firm market value for Chinese versus U.S. internet platforms. Applying an event study approach to daily stock market data during 2010-2022, we investigate the cumulative abnormal returns of Hong Kong- and U.S.-listed internet platforms. We find that the launch of an antitrust investigation in China causes a significant decrease in the investigated firm's market value but boosts the market value of its competitors; while the end of the investigation increases the investigated firm's market value but dampens the market value of other leading platforms that involve the alleged exclusive dealing conduct. A similar analysis on U.S. internet platforms shows minor effects of EU/U.S. antitrust regulations and actions. These results indicate that differences in enforcement duration and uncertainty of antitrust enforcement matter. Stronger stock market reactions to Chinese versus EU/U.S. antitrust legislation are also observed, which suggests investors' belief in the Chinese antitrust authority's stronger discretion in antitrust enforcement.{\textcopyright} The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature2025, Corrected publication 2025",

keywords = "Administrative enforcement, Antitrust regulation, Event study, Internet platform, Judicial remedies, Market value, L41, L44, G14, G11",

author = "Yong Huang and Nina Yin and Zhang, {Vanessa Yanhua} and Shan Zhao",

year = "2025",

month = oct,

doi = "10.1007/s11151-025-10035-z",

language = "English",

volume = "67",

pages = "251--288",

journal = "Review of Industrial Organization",

issn = "0889-938X",

publisher = "Springer Netherlands",

number = "3",

}

TY - JOUR

T1 - Impact of Antitrust Events on Firm Market Value

T2 - Evidence from Chinese and US Internet Platforms

AU - Huang, Yong

AU - Yin, Nina

AU - Zhang, Vanessa Yanhua

AU - Zhao, Shan

PY - 2025/10

Y1 - 2025/10

N2 - This study compares the effect of antitrust regulations on firm market value for Chinese versus U.S. internet platforms. Applying an event study approach to daily stock market data during 2010-2022, we investigate the cumulative abnormal returns of Hong Kong- and U.S.-listed internet platforms. We find that the launch of an antitrust investigation in China causes a significant decrease in the investigated firm's market value but boosts the market value of its competitors; while the end of the investigation increases the investigated firm's market value but dampens the market value of other leading platforms that involve the alleged exclusive dealing conduct. A similar analysis on U.S. internet platforms shows minor effects of EU/U.S. antitrust regulations and actions. These results indicate that differences in enforcement duration and uncertainty of antitrust enforcement matter. Stronger stock market reactions to Chinese versus EU/U.S. antitrust legislation are also observed, which suggests investors' belief in the Chinese antitrust authority's stronger discretion in antitrust enforcement.© The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature2025, Corrected publication 2025

AB - This study compares the effect of antitrust regulations on firm market value for Chinese versus U.S. internet platforms. Applying an event study approach to daily stock market data during 2010-2022, we investigate the cumulative abnormal returns of Hong Kong- and U.S.-listed internet platforms. We find that the launch of an antitrust investigation in China causes a significant decrease in the investigated firm's market value but boosts the market value of its competitors; while the end of the investigation increases the investigated firm's market value but dampens the market value of other leading platforms that involve the alleged exclusive dealing conduct. A similar analysis on U.S. internet platforms shows minor effects of EU/U.S. antitrust regulations and actions. These results indicate that differences in enforcement duration and uncertainty of antitrust enforcement matter. Stronger stock market reactions to Chinese versus EU/U.S. antitrust legislation are also observed, which suggests investors' belief in the Chinese antitrust authority's stronger discretion in antitrust enforcement.© The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature2025, Corrected publication 2025

KW - Administrative enforcement

KW - Antitrust regulation

KW - Event study

KW - Internet platform

KW - Judicial remedies

KW - Market value

KW - L41

KW - L44

KW - G14

KW - G11

UR - https://www.webofscience.com/wos/woscc/full-record/WOS:001591981000001

U2 - 10.1007/s11151-025-10035-z

DO - 10.1007/s11151-025-10035-z

M3 - RGC 21 - Publication in refereed journal

SN - 0889-938X

VL - 67

SP - 251

EP - 288

JO - Review of Industrial Organization

JF - Review of Industrial Organization

IS - 3

ER -

Impact of Antitrust Events on Firm Market Value: Evidence from Chinese and US Internet Platforms

Abstract

Funding

Research Keywords

Access Output

Other Access Options

Permanent Link

Other Files and Links

Fingerprint

Cite this