Stock indexes were little changed on Friday as a Group of 20 nations meeting that sought a common path to manage global trade, currency and macroeconomic imbalances kept investors skittish and markets choppy.
The S&P 500 sent a bullish signal as the index's 50-day moving average crossed above its 200-day moving average, a technical event known as a golden cross. That upward momentum indicator last occurred in June 2009, and the benchmark rose more than 35 percent in the following 10 months.
"The driver of the stock market since September has been quantitative easing (QE), and one of its effects is a weaker (U.S.) currency," said Gary Flam, portfolio manager at Bel Air Investment Advisors in Los Angeles.
"People are considering a lot of QE priced in. It's a very low conviction market, and that has been causing lots of swings."
The U.S. dollar zigzagged against a basket of currencies (.DXY) on wariness over what, if any, deal would be reached at the G20 rich and emerging nations meeting in South Korea. The euro also traded choppily against the greenback.
The Dow Jones industrial average (.DJI) dropped 12.87 points, or 0.12 percent, to 11,133.70. The Standard & Poor's 500 (.SPX) gained 1.27 points, or 0.11 percent, to 1,181.53. The Nasdaq Composite (.IXIC) rose 5.52 points, or 0.22 percent, to 2,465.19.
Buoying the Nasdaq, SanDisk Corp (SNDK.O) gained 1.5 percent to $37.68 and Baidu Inc (BIDU.O) rose 5 percent to $107.57 a day after both companies posted results.
Two top U.S. Federal Reserve officials gave competing views on the need for more stimulus for the economy, continuing a public debate over further monetary easing, even though the Fed's core view appears to favor such a move.
Growing speculation in recent weeks that the Fed will extend the quantitative easing measures at its next meeting in November has pressured the dollar while boosting equities, but uncertainty over the extent of the stimulus has caused some market volatility.
Equity markets have traded of late in tandem with the euro, with S&P futures rising along with Europe's single currency.