After-hours buzz: Yum, CSX, Celgene & more

Check out the companies making headlines after the bell Tuesday:

Traders work the floor of the New York Stock Exchange.
Adam Jeffery | CNBC
Traders work the floor of the New York Stock Exchange.

Yum Brands - The fast food operator, which owns Taco Bell, KFC and Pizza Hut brands, handed in second-quarter earnings of 69 cents a share, topping estimates of 62 cents a share, but revenue trailed projections. The company said comparable-store sales in China declined 10 percent, which was more than the 8 percent decrease Wall Street projected. The stock fell about 1 percent in extended-hours trading.

CSX - The railroad supplier reported adjusted second-quarter earnings of 56 cents a share on $3.06 billion in revenue. Analysts were looking for profit of 53 cents a share on $3.12 billion in sales. The stock rose about 4 percent in after-hours trading.

Celgene - The pharmaceutical providersaid it would acquire Receptos, which develops treatments for immune disorders, for more than $7 billion. That's about a 12 percent premium to Receptos' closing price on Tuesday. Celgene rose about 5 percent after hours, while Receptos jumped 11 percent after being halted for the news.

Allegheny Technologies - The materials supplier said it expects a second-quarter loss of between 15 cents and 17 cents a share, citing challenges related to its flat-rolled products business and further weakening in demand from the oil and gas market. The stock fell about 9 percent.

Cummins - Shares ticked higher after the maker of diesel engines raised its quarterly cash dividend to 97.5 cents from 78 cents a share.

Ultragenyx Pharmaceutical - The stock fell about 3 percent after the biotech firm proposed a public offering of up to $250 million of shares of its common stock.