After-hours buzz: HCSG, HUM & more

Traders on the floor of the New York Stock Exchange.
Brendan McDermid | Reuters
Traders on the floor of the New York Stock Exchange.

Check out which companies are making headlines after the bell:

Shares of Healthcare Services Group rose more than 4 percent in extended trading after beating per-share estimates from Thomson Reuters on its second-quarter earnings report. The company said its quarterly revenue rose nearly 22 percent from the year before to $470.88 million.

Shares of science manufacturer Agilent fell nearly 3 percent during extended trading. Earlier Monday, its "overweight" stock rating was restated by Morgan Stanley.

Paccar shares tumbled more than 2 percent in extended trading. S&P said Tuesday afternoon that it had assigned a stable rating to its financing subsidiary.

Shares of Humana fell nearly 3 percent in after-hours trading after Central Bank & Trust cut its stake in the health care provider by 5.6 percent, according to a recent filing with the Securities and Exchange Commission.

Shares of NRG Energy jumped more than 3 percent in extended trading after the company announced that it would release the results of its business review to transform the company in a conference call Wednesday.