Allison Transmission Holdings Inc. (ALSN) suffered an 8.53% plunge in the after-hours trading session on Tuesday, despite reporting better-than-expected fourth quarter 2024 earnings results. The after-hours sell-off appears to be driven by the company's full-year 2025 revenue outlook, which may have fallen short of analyst expectations.

For the fourth quarter, the automatic transmission maker reported earnings of $2.01 per share, surpassing the consensus analyst estimate of $1.93 per share. Quarterly revenue of $796 million also exceeded expectations of $791.2 million. For the full year 2024, Allison Transmission posted a profit of $731 million, or $8.31 per share, on revenue of $3.23 billion.

However, the company's full-year 2025 revenue guidance range of $3.2 billion to $3.3 billion appears to have disappointed investors, potentially signaling slower growth expectations. Analysts may have been anticipating a more robust outlook for the coming year, leading to the sharp sell-off in the after-hours session.