Check out which companies are making headlines after the bell:
Shares of CSX fell more than 4 percent in extended trading. The rail transport company beat Thomson Reuters consensus estimates with earnings of 64 cents per share and revenue of $2.93 billion in its quarterly earnings report. CSX posted softer-than-expected second-half guidance, however.
Shares of Vertex Pharmaceuticals skyrocketed more than 24 percent in extended trading after the company said on Tuesday that a new drug cocktail in patients with cystic fibrosis.
United Continental's shares fell nearly 4 percent in after-hours trading. The company posted higher-than-expected earnings and revenue for the second quarter.
Shares of IBM fell more than 2.5 percent in extended trading after the company reported its in a quarterly earnings report. The company reported earnings of $2.97 per share, well above consensus analyst estimates of $2.74 from Thomson Reuters. IBM's revenue, however, came in below expectations at $19.29 billion.