By Barbara Kollmeyer, MarketWatch

Nasdaq, S&P 500 futures drop over 1% in 20-minute stretch

MADRID (MarketWatch) -- U.S. stock futures fell early Wednesday after wild moves during Asian trading hours that came as the dollar pitched lower against the yen.

Futures for the Dow Jones Industrial Average (YMM5) fell 97 points, or 0.6%, to 17,604, while those for the S&P 500 index (ESM5) fell 12.3 points, or 0.6%, to 2,048.25.

Futures for the Nasdaq-100 (NQM5) lost 28.50 points, or 0.7%, to 4,300.25.

But moves in Asia trading hours were far more dramatic. "It's not every day you see Nasdaq and S&P futures dropping 1.3% in around 20 minutes, and 0.7% in three minutes, especially when risk FX (such as AUD/USD) or copper didn't go along for the ride," IG chief market strategist Chris Weston said in a note.

He said there was a lot of "head-scratching" going on over just what triggered the move. The futures' drop coincided with a fall for the U.S. dollar against the yen (USDJPY). A lackluster reading (http://www.marketwatch.com/story/japans-tankan-sentiment-survey-shows-few-gains-2015-03-31) from the Bank of Japan's tankan corporate sentiment survey prompted investors to buy the yen, a perceived safe haven. The yen began falling as soon as Japan stocks opened Wednesday.

Weston said one could suggest the initial move came from the drop in dollar/yen, but he believes it was actually stock futures driving the dollar action.

Appetite for riskier investments was already weak in Asia after sizeable losses Tuesday (http://www.marketwatch.com/story/us-stocks-fed-speakers-iran-keep-investors-on-edge-as-quarter-ends-2015-03-31) for Wall Street. The S&P 500 (SPX) finished down 18.35 points, or 0.9%, at 2,067.89, though it still managed a quarterly gain of 0.4% for the ninth-straight winning quarter.

Later Wednesday, investors will get another big batch of U.S. data -- ADP employment for March at 8:15 a.m. Eastern Time, which comes ahead of Friday's nonfarm payrolls data, then the Markit Purchasing Managers Index survey at 9:45 a.m. Eastern.

At 10 a.m., the Institute for Supply Management's manufacturing index for March will be released, along with construction spending for February.

Subscribe to WSJ: http://online.wsj.com?mod=djnwires