Stocks making the biggest moves premarket: Twitter, Boeing, Spark, Boston Beer, Snap & more

Check out the companies making headlines before the bell:

Twitter – Twitter said the personal account of CEO Jack Dorsey is now secure after being hacked on Friday. The hacker used Dorsey's account to send out tweets that contained racist messages.

Boeing – Boeing faces new delays in returning the 737 Max to service, according to The Wall Street Journal. International regulators are said to be upset over what they perceive as a lack of information from Boeing on its proposed software fixes for the grounded jet.

Spark Therapeutics – Spark and Switzerland's Roche announced another extension of Roche's $4.3 billion takeover bid for the U.S.-based gene therapy company. The extension to October 1 was given to provide more time for regulatory reviews.

Royal Caribbean, Norwegian Cruise Line, Carnival – The cruise lines could see an estimated impact of 5 cents per share from Hurricane Dorian for the current quarter, according to an analyst report from Nomura Instinet.

Las Vegas Sands, Wynn Resorts – These and other casino operators who operate in Macau may be negatively impacted by news of a bigger than expected 8.6% August decline in gaming revenue compared to a year earlier.

Amazon.com – The stock's price target was raised to $2,600 per share from $2,250 by RBC Capital Markets, which also reiterated its "outperform" rating on the stock. The move reflects the expected positive impact of Amazon's new "Prime One-Day Shipping" initiative.

Nexstar Media – Federal Communications Commission Chairman Ajit Pai is seeking approval from his fellow commissioners for Nexstar's proposed $6.4 million acquisition of rival TV station operator Tribune Media. The deal has already gained conditional Justice Department approval, with the companies required to divest TV stations in 13 markets to address antitrust concerns.

Boston Beer – The beer brewer's stock was downgraded to "underperform" from "hold" at Jefferies, which points to increased competition in the alcoholic seltzer drink category. Jefferies also cut its price target on the stock to $332 per share from $360.

Snap – The Snapchat parent's shares were upgraded to "outperform" from "in-line" at Evercore, which is citing Snap's move into gaming.

Western Digital – The disk drive and memory chip maker was upgraded to "in-line" from "underperform at Evercore, which is optimistic about NAND flash memory pricing.

Conn's – The furniture and home appliance retailer reported quarterly profit of 62 cents per share, 11 cents a share above estimates. Revenue also beat Wall Street forecasts, boosted by new stores, which more than made up for a 2.3% decline in same-store sales.

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