US stocks finished lower Thursday, with BlackBerry maker Research in Motion losing 5.8 percent after launching a new operating system and Dow Chemical sagging nearly 7 percent on a quarterly loss.
The Dow Jones Industrial Average finished down 49.84 points (0.36 percent) to 13,860.58.
The broad-based S&P 500 dropped 3.85 points (0.26 percent) to 1,498.11.
The tech-heavy Nasdaq Composite slipped 0.18 (0.01 percent) to 3,142.13.
Facebook, which reported disappointing earnings after the close Wednesday, pulled back from an early sharp fall to end down just 1.1 percent.
The Justice Department's filing of a suit to block the $20 billion takeover of Mexican brewer Grupo Modelo by the world's largest beer group, Anheuser-Busch InBev, sent their shares tumbling.
US anti-trust authorities said the merger would give ABI control of nearly 50 percent of the US beer market.
ABI shares lost 5.9 percent, and on Mexico's Bolsa, Grupo Modelo lost 6.7 percent.
The biggest casualty of the Justice Department's move was Constellation Brands, which was expected to gain control of the US importer of Modelo products -- which include Corona -- in the deal.
Constellation shares finished down 17.4 percent.
Other companies reporting earnings whose shares fell included ConocoPhillips (-5.1 percent) and Time Warner Cable (-11.3 percent).
Among key gainers, chipmaker Qualcomm's shares added 3.9 percent after several brokers gave it an upgrade following its strong quarterly results.
Casino operators Las Vegas Sands added 7.2 percent after beating revenue growth forecasts helped by a new China operation, despite missing expectations on the bottom line.
Bond prices edged higher. The yield on the 10-year US Treasury slipped to 1.99 percent from 2.01 percent late Wednesday, while the 30-year fell to 3.17 percent from 3.20 percent. Bond prices and yields move inversely.