Stocks making the biggest moves after hours: THO, UNH & more
A factory worker installs rivets into the roof of an Airstream Inc. RV travel trailer on the production line at the company's assembly plant in Jackson Center, Ohio.

Check out the companies making headlines after the bell Monday.

Shares of Thor Industries soared more than 10 percent in after-hours trading, after the Indiana-based recreational vehicle manufacturer posted record earnings and revenue that beat Wall Street expectations.

UnitedHealth Group shares slipped more than 1 percent in extended trading, after the health-insurance giant revealed a lighter-than-expected earnings forecast for 2018.

Tech Data shares climbed more than 4.5 percent after the bell Monday, after the IT distribution company posted third-quarter financial results.

Shares of Iqvia Holdings slipped more than 1 percent after the bell. The biopharmaceutical development and commercial outsourcing services provider announced a new share-buyback program.