Research

Working papers and selected research projects.

Working papers

Heterogeneous AI News and Hub Formation: Event-Day Causal Network Evidence on the Magnificent Seven
2026

Milán Csaba Badics and Márton Espán

Abstract. Major AI announcements now rank among the key information events for equity markets, yet little is known about their firm-level transmission on the announcement day itself. This paper asks whether different AI-news types affect different subsets of AI-exposed firms, whether information transmission is centralized around Magnificent Seven (M7) stocks, and whether the main source node depends on the event type. Using high-frequency intraday data for M7 stocks and smaller AI-exposed firms, we estimate event-day networks with a DAG-based Directed R2 connectedness framework. The evidence shows that AI news does not follow a single market-wide transmission channel: the main source node changes across event types. M7 firms emerge as event-day hubs in compute and adoption-related events, whereas disruption-related information can shift the main source node to a non-M7 firm. The results indicate that AI-related information is transmitted through event-specific equity-market channels, creating spillover vulnerabilities when information transmission is organized around a few dominant source nodes.

Replication files