The New York Stock Exchange (NYSE) is reflected in a puddle in New York, U.S., on Monday, June 18, 2018.

Check out the companies making headlines after the bell:

Energen surged more than 7 percent in after-hours trading after Diamondback Energy announced it was acquiring the oil and gas company for about $9.2 billion, including debt, or $84.95 per share. The acquisition price represents a 16.1 percent premium to Tuesday's closing price of $73.14. The all-stock deal is expected to close by the end of the fourth quarter of this year. Diamondback's stock, meanwhile, lost 7.3 percent.

Teva Pharmaceuticals rose 1.2 percent after a regulatory filing showed Warren Buffett's Berkshire Hathaway increased its position by 6.7 percent during the second quarter. Teva's stock later pared its gains. The filing also showed Berkshire increased its stake in Southwest Airlines and Delta Air Lines, which rose 1.18 percent and 1.86 percent, respectively, in after-hours trading.

Lighting products company Cree slipped more than 1 percent after the bell as the company issued disappointing revenue guidance for its fiscal first quarter. The company said it expects sales to range between $395 million and $415 million, below a FactSet estimate of $416 million.

Shares of Agilent Technologies initially ticked 0.3 percent higher after the bell upon the release of its fiscal third-quarter earnings. The company reported a profit of 67 cents per share. Analysts polled by Reuters expected earnings per share of 63 cents. Revenue matched estimates at $1.2 billion. CEO Mike McMullen said Agilent's results were driven by its China business as well as strength in "the global pharma and chemical & energy end markets." The stock later erased its slight gains and traded 0.2 percent lower, however.



Correction: Diamondback Energy is buying Energen in an all-stock deal. A previous version of this story misstated the type of deal.