The Palm Beach Gardens, Fla., company reported earnings rose to $1.06 a share from 76 cents in the year-earlier quarter. Revenue of $810.3 million declined from $884.1 million.
Analysts surveyed by FactSet were expecting the company to report earnings of $1.05 a share on revenue of $817.7 million.
Dycom shares at last check dropped 17% to $64.38. Before Tuesday's decline, Dycom shares had risen more than 65% year to date.
The company, which provides contracting services including program management, engineering, construction, maintenance and other services for telecommunications providers, also said that it expected "modestly lower" contract revenues in the fourth quarter.
Wall Street is expecting the company to report earnings of 23 cents a share on revenue of $744.1 million for the quarter.
The "impact of the covid-19 pandemic on its operating results, cash flows and financial condition is uncertain, unpredictable and could affect its ability to achieve these expected financial results," Dycom said in its earnings release.