Armstrong World Industries' stock experienced a significant pre-market plunge of 6.50% on Tuesday. The sharp decline followed the release of the company's first-quarter 2026 financial results.

The ceilings and architectural products maker reported adjusted earnings per share of $1.69 for the quarter, missing the analyst consensus estimate of $1.81. While net sales of $409.9 million slightly exceeded expectations, profitability was pressured by non-recurring costs.

Operating income declined 4.4% to $94.2 million, impacted by severance expenses, acquisition-related costs, and a tariff adjustment. The Architectural Specialties segment faced particular margin pressure, with operating income dropping 37.2% despite double-digit sales growth, attributed to short-term headwinds during the quarter.