Check out the companies making headlines before the bell:

Alphabet — The Google-parent reported better-than-expected earnings but its stock dropped nearly 8% in the premarket after posting a slowdown in advertising revenue growth. The company said its ad revenue grew by 15.3% in the first quarter, down from 24.4% in the year-earlier period.

General Electric — The industrial giant reported better-than-expected quarterly results as the company works to simplify its business and turn around the company. CEO Larry Culp also reaffirmed General Electric's 2019 forecast, sending the stock up 8.5%.

AK Steel — Shares of the steel company rose 3.7% in the premarket after reporting earnings per share for the previous quarter that beat expectations. The company's results got a boost from higher prices.

MGM Resorts International — The casino operator's stock fell 3.2% on a big miss on quarterly earnings. MGM posted a profit of 5 cents per share, while analysts polled by Refinitiv expected earnings of 21 cents per share.

Western Digital — Shares of the data storage company fell about 5.5% on the back of weaker-than-expected fiscal third quarter results. Western Digital posted adjusted earnings per share of 17 cents on revenue of $3.67 billion. Analysts expected a profit of 46 cents per share on sales of $3.68 billion.

Yum China — Yum China posted first-quarter numbers that topped estimates amid strong performances from key businesses like KFC and Pizza Hut. The company posted adjusted earnings per share of 59 cents on revenue of $2.3 billion. Analysts polled by Refinitiv expected a profit of 54 cents per share on sales of $2.26 billion. Same-store sales rose 4% in the quarter, well above a forecast of 1.8%.

ConocoPhillips — ConocoPhillips shares rose 1.5% on the back of better-than-expected earnings and revenue. The company earned $1 per share on revenue of $10.1 billion. Analysts had forecast a profit of 90 cents per share and revenue of $9.039 billion.

Eli Lilly — Eli Lilly reported quarterly earnings that topped expectations and raised its full-year profit guidance. However, the stock fell more than 3% as revenue came in just below expectations.

McDonald's — The Dow Jones Industrial Average component posted stronger-than-forecast results for the first quarter as same-store sales grew at a stronger pace than expected. McDonald's earnings came in at $1.78 per share, 3 cents above a Refinitv estimate. Sales for the company totaled $4.956 billion, topping a $4.933 billion forecast.

MasterCard —The credit card company posted quarterly earnings and revenue that topped analysts' expectations, sending its stock up more than 1%. MasterCard reported earnings per share of $1.78 on revenue of $3.899 billion. Analysts polled by Refinitiv expected a profit of $1.66 per share on revenue of $3.856 billion.