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 improved lung function 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 21st consecutive quarter of declining revenue 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.