US stocks flat despite giant Heinz, airline deals

US stocks traded flat Thursday despite the excitement from two giant M&A deals, the merger of American Airlines and US Airways, and Berkshire Hathaway and 3G's takeover of ketchup maker Heinz.

Analysts said the markets were partly echoing the slump in European markets on dismal economic growth reports from eurozone countries, as well as Japan.

At the close, the Dow Jones Industrial Average was down 9.52 points (0.07 percent) at 13,973.39.

The broad-based S&P 500 added 1.05 (0.07 percent) to reach 1,521.38, while the tech-rich Nasdaq Composite gained 1.78 points (0.06 percent) to 3,198.66.

US Airways shares fell 4.6 percent after the official announcement of its long-awaited merger with American Airlines, creating the largest US carrier.

American parent AMR Corp, under bankruptcy reorganization, jumped 57 percent.

Heinz shares soared nearly 20 percent to $72.49 after the shock announcement that billionaire Warren Buffett's investment firm would partner with 3G Capital to buy Heinz in a $28 billion deal.

Berkshire Hathaway and 3G said they would offer shareholders $72.50 a share.

Berkshire's B shares finished up 1.2 percent.