[Paper Review] Breaking news

Lars Winkelmann, Wenying Yao|arXiv (Cornell University)|Mar 24, 2026

Financial Markets and Investment Strategies0 citations

TL;DR

The paper analyzes how regulatory dynamic circuit breakers in high-frequency markets affect price discovery and develops a regression-based test for fundamental pricing that accounts for non-vanishing transition times, with empirical evidence of overshooting during Breaking news events in CME E-mini S&P 500 futures.

ABSTRACT

This paper examines how regulatory interventions in high-frequency financial markets affect price discovery. We focus on Breaking news, where dynamic circuit breakers trigger trading halts immediately after the release of macroeconomic fundamentals. Within a high-frequency signal-in-noise model, we show that triggering rules complicate statistical inference for the price impact of news, rendering conventional non-parametric jump estimators inconsistent. Building on this insight, we develop a regression-based test for fundamental pricing that accounts for non-vanishing transition times. The test compares transition price changes to efficient jumps implied by observable factors. Our empirical analysis of CME E-mini S\&P 500 futures shows that Breaking news are associated with systematic deviations from fundamental pricing, predominantly in the form of overshooting. Our findings highlight a regulatory trade-off: the appeal of simple and transparent circuit breaker rules must be weighed against their cost of preventing fundamentals from being priced contemporaneously, thereby creating adverse incentives and introducing distortions.

Motivation & Objective

• Motivate the study of regulatory interventions (dynamic circuit breakers) on price discovery in high-frequency markets.
• Understand how Breaking news events alter price formation and whether prices reflect fundamentals.
• Develop inference methods that are robust to non-vanishing transition times in price changes during news releases.
• Provide empirical evidence from CME E-mini S&P 500 futures on deviations from fundamental pricing during Breaking news.

Proposed method

• Embed a high-frequency signal-in-noise model to capture price formation under circuit breakers.
• Show that triggering rules bias conventional non-parametric jump estimators and complicate inference.
• Develop a regression-based test for fundamental pricing that accommodates non-vanishing transition times.
• Compare observed transition price changes to efficient jumps implied by observable factors to test pricing accuracy.
• Apply the method to CME E-mini S&P 500 futures data to detect deviations from fundamentals during Breaking news events.

Experimental results

Research questions

• RQ1 Do dynamic circuit breakers during Breaking news affect contemporaneous pricing relative to fundamentals?
• RQ2 Can a regression-based test detect fundamental pricing deviations when transition times are non-vanishing?
• RQ3 Are there systematic price distortions, such as overshooting, associated with Breaking news in futures markets?

Key findings

• Breaking news are associated with systematic deviations from fundamental pricing in CME E-mini S&P 500 futures.
• Deviations predominantly take the form of overshooting according to the empirical analysis.
• Dynamic circuit breakers complicate price discovery and can introduce distortions by hindering contemporaneous pricing of fundamentals.
• Conventional non-parametric jump estimators become inconsistent under the presence of trading halts triggered by news.
• The regression-based test accounts for non-vanishing transition times and provides a framework to assess fundamental pricing in the presence of Breaking news.