Stocks making the biggest moves premarket: American Express, Verizon, Twitter and more
Check out the companies making headlines before the bell:

American Express (AXP) – American Express rallied 4.5% in the premarket after beating top and bottom line estimates for the second quarter. Card members registered record spending, driven by a rebound in travel and entertainment.

Verizon (VZ) – Verizon fell 4.4% in the premarket after adjusted quarterly earnings fell short of estimates and the company cut its full-year forecast. Verizon is seeing its phone subscriber growth impacted by higher prices.

Twitter (TWTR) – The social media stock fell 2% in premarket trading after the company reported disappointing second-quarter results. Twitter posted a loss of 8 cents, compared to an expected earnings of 14 cents, according to Refinitiv. Its revenue slid 1% year-over-year to $1.18 billion, which fell short of analysts' projected $1.32 billion. Twitter partially blamed the revenue drop on ad industry headwinds tied to the broader macro environment, as well as uncertainty related to the pending take-over deal by Elon Musk.

Schlumberger (SLB) – The oilfield services company reported better-than-expected profit and revenue for the second quarter and raised its full-year outlook. Schlumberger is benefiting from increased demand for its services amid higher oil prices. Its stock added 2.3% in premarket trading.

HCA Healthcare (HCA) – HCA surged 11.4% in the premarket after beating top and bottom line estimates for its latest quarter. The hospital operator's better-than-expected results came despite labor market and inflation challenges.

Cleveland-Cliffs (CLF) – The mining company's stock slid 5.3% in premarket action after its latest quarterly earnings fell short of Street forecasts, though revenue beat consensus estimates. Cleveland-Cliffs noted its exposure to the auto sector, where supply chain issues have constrained production, and said it expects to benefit as those issues resolve.

Snap (SNAP) – Snap tumbled 30.3% in the premarket after the Snapchat parent reported a wider-than-expected quarterly loss and its slowest sales growth since going public. It also said current quarter sales are on pace for a flat performance, compared with a year ago, amid tougher economic conditions and growing competition for digital ad dollars.

Mattel (MAT) – Mattel fell 1% in premarket trading despite a better-than-expected quarterly performance and strong sales of movie-themed toys. However, sales of its American Girl brand slid nearly 20% during the quarter.

Seagate Technology (STX) – Seagate Technology slumped 11.8% in premarket action trading after the disk drive maker missed quarterly estimates on both the top and bottom lines. It also issued a weaker-than-expected forecast as demand wanes for products like personal computers.

Tenet Healthcare (THC) – The hospital operator nearly doubled the 82-cent consensus estimate with an adjusted quarterly profit of $1.50 per share. Tenet said it was able to navigate through challenging market conditions as well as a cyber attack. Its stock surged 10.9% in the premarket.

Intuitive Surgical (ISRG) – Intuitive Surgical missed estimates on both the top and bottom lines for its latest quarter, as placements of its Da Vinci robotic surgical systems fell. The company said Covid resurgences are impacting the number of procedures performed with the system, and its shares tumbled 12.1% in premarket trading.

Boston Beer (SAM) – Boston Beer took a 9.6% premarket hit after reporting lower-than-expected earnings for its latest quarter and cutting its full-year forecast. Waning demand for its Truly hard seltzer brand continues to impact overall performance for the brewer of Sam Adams beer.