Check out the companies making headlines in after-hours trading. Discover Financial Services — Shares of Discover Financial Services rose 2.7% after the company reported second-quarter results. The bank and payments company reported net interest income of $3.52 billion, beating the FactSet consensus estimate of $3.46 billion. Earnings per share were $6.06, beating analysts’ expectations of $3.10 per share. Kinder Morgan — Kinder Morgan shares fell 2.8% after the company reported quarterly results that fell short of expectations. The pipeline operator reported second-quarter adjusted earnings of 25 cents a share, below the 26 cents a share expected by analysts polled by FactSet. Revenue also fell short of expectations. United Airlines – Shares of United Airlines edged down 0.3% after the airline reported mixed second-quarter results. The company reported second-quarter adjusted earnings of $4.14 per share, beating the LSEG consensus estimate of $3.93 per share. However, revenue of $14.99 billion fell short of expectations of $15.06 billion. Steel Dynamics — Shares of the steelmaker rose nearly 2%. Steel Dynamics reported second-quarter earnings of $2.72 per share on revenue of $4.63 billion. Analysts polled by London Stock Exchange Group (LSEG) expected earnings of $2.67 per share on revenue of $4.43 billion. Alcoa — The aluminum company edged up 1.5%. Alcoa reported adjusted earnings of 16 cents per share, beating analysts’ expectations of 9 cents per share (on an LSEG basis). Revenue also topped expectations, at $2.91 billion, compared with analysts’ forecasts of $2.84 billion. —CNBC’s Darla Mercado contributed reporting.