Research reveals that CEO vocal characteristics during earnings calls significantly impact stock prices, beyond what transcripts convey. The study analyzes acoustic features like assertiveness, nervousness, and arousal levels from unscripted Q&A segments. These vocal signals reflect internal company uncertainty that traditional financial metrics miss.

Published in the Journal of Portfolio Management, the research shows investors systematically underreact to confidence signals expressed through tone. David Pope, formerly of S&P Global Market Intelligence, now runs Speech Craft Analytics and led the analysis. By extracting paralinguistic acoustic features, the study demonstrates that vocal delivery contains distinct economic information.

Corporate executives now face fresh pressure to master not just their words but their vocal delivery. Beyond balancing transparency with caution, they must modulate assertiveness, valence, and arousal levels during calls. The research suggests transcripts alone fail to capture the full spectrum of managerial communication that drives market reactions.

This algorithmic scrutiny transforms earnings calls into high-stakes performances where every vocal nuance gets parsed for hidden meaning.