* Shire shares tumble as AbbVie reconsiders bid
* Retail sales drop more than expected in September
* Producer prices fall for first time in over a year
* Indexes off: Dow 1.15 pct, S&P 1.15 pct, Nasdaq 1.09 pct (Updates to open)
By Chuck Mikolajczak
NEW YORK, Oct 15 (Reuters) - U.S. stocks dropped on Wednesday, with each of the major U.S. indexes briefly falling more than two percent, as economic data reinforced worries over the health of the world economy and on signs of slowing merger activity.
The declines sent the S&P and Nasdaq composite indexes into negative territory for the year, while the Dow Industrials fell into the red for 2014 on Friday. The benchmark S&P 500 has lost more than 7 percent since its Sept. 18 record closing high.
The S&P 500 had eked a tiny gain at the close a day earlier following three sessions of declines spurred by concern over plunging oil prices, the potential impact of global economic weakness on U.S. earnings and the spread of Ebola.
Aside from concerns about the global economy, Chicago-based AbbVie said it was reconsidering its $55 billion takeover of the company weeks after the U.S. government moved to curb deals designed to reduce tax, throwing the vitality of merger and acquisition activity into doubt.
U.S.-listed shares of Shire tumbled 22.5 percent to $189.57 while AbbVie shares declined 2.3 percent to $52.89.
Concerns about a slowing global economy weren't helped by economic data that showed retail sales fell 0.3 percent in September, worse than an expected 0.1 percent decline. Also, producer prices fell in September for the first time in over a year, a sign inflation may be having difficulty gaining traction, while manufacturing activity in New York slowed to its weakest pace since April.
"We had Empire State manufacturing coming in much lower than expected, we had retail sales coming in lower than expected, so there were signs, with this recent data, of an economic slowdown," said Andre Bakhos, managing director at Janlyn Capital LLC in Bernardsville, New Jersey.
"You couple this with fears about the spread of Ebola, with the recent downtrend and what we had today, the mindset has been a flight to safety and cash is certainly a safe place to be in."
In earnings news, Bank of America shares were off 3 percent to $16.03 after posting its third-quarter results.
S&P 500 companies are expected to show earnings growth of 6.4 percent in the third quarter, according to Thomson Reuters data, with revenue growth expected at 4 percent.
Later in the session at 2:00 p.m. (1800 GMT) the Federal Reserve's Beige Book on business activity across the nation is expected.
At 9:52 a.m. EDT, the Dow Jones industrial average fell 188.38 points, or 1.15 percent, to 16,126.81, the S&P 500 lost 21.65 points, or 1.15 percent, to 1,856.05 and the Nasdaq Composite dropped 46.13 points, or 1.09 percent, to 4,181.05.
The largest percentage gainer on the S&P 500 was Southwestern Energy, which rose 2.1 percent, while the largest percentage decliner was KeyCorp, down 6.3 percent after its quarterly results.
The largest percentage gainer on the Nasdaq 100 was NXP Semiconductor, up 1.6 percent, while the largest percentage decliner was Liberty Interactive, down 3.5 percent.
Declining issues were outnumbering advancing ones on the NYSE by 2,515 to 435, for a 5.78-to-1 ratio on the downside; on the Nasdaq, 1,910 issues were falling and 513 advancing for a 3.72-to-1 ratio favoring decliners.
The benchmark S&P 500 index was posting 2 new 52-week highs and 68 new lows; the Nasdaq Composite was recording 2 new highs and 192 new lows. (Additional reporting by Yasmeen Abutaleb; Editing by Bernadette Baum)