The major averages extended opening losses after disappointing morning data. Chicago PMI for April was 50.4, below expectations of 53.0 and March's 53.6 print. The final April read on consumer sentiment was 89.0.
"Today's market action we're seeing a cross section of profit-taking ... and weakness," said Lance Roberts, chief investment strategist at Clarity Financial.
The U.S. dollar index fell more than half a percent Friday to post a monthly loss of about 1.6 percent, its first three-month losing streak since 2012.
The euro was last near $1.144. Earlier, the euro hit its highest against the dollar since April 12 and the dollar index fell to its lowest since Aug. 24, 2015.
The dollar lost nearly 4.9 percent against the yen for the week, its worst since October 2008.
The Japanese yen strengthened to fresh highs against the U.S. dollar, going back to October 2014, and was last near 106.4 yen against the greenback.
"The biggest surprise of the week was the Bank of Japan. We're still feeling the aftershocks of that," said Art Hogan, chief market strategist at Wunderlich Securities.
Ahead of the U.S. market open Thursday, the Bank of Japan kept policy unchanged, maintaining the pace of its asset purchase program and keeping steady its 0.1 percent negative rate it applies to some deposits. The central bank also cut its inflation forecasts and again pushed back the timing for hitting its 2 percent price target by six months.
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It's "somewhat of a risk-off week probably led by the inaction of the Bank of Japan," said Eric Stein, co-director of global fixed income at Eaton Vance Management.
Gold jumped more than 2 percent in intraday trade to hit its highest in more than a year, going back to Jan. 26, 2015.
Gold futures for June delivery settled up $24.10 at $1,290.50 an ounce. Gold gained 4.44 percent in April, for its first four-month win streak since the one ended August 2012.
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In earnings news, Amazon.com reported earnings well above expectations on both the top and bottom line, helped by growth in its Amazon Web Services business. First-quarter earnings of $1.07 a share on $29.13 billion in revenue compares with last year's loss of 12 cents a share and $22.72 billion in sales.
LinkedIn's results also soared past expectations and the firm raised its full-year outlook. Shares closed nearly 1.9 percent higher, but are more than 44 percent lower for the year so far.
Chevron posted a greater-than-expected loss of 39 cents a share, while revenue beat expectations at $23.55 billion. That marked a roughly 32 percent decline in sales from the comparable year-ago figure of $34.56 billion. The stock closed 0.2 percent lower but are still up more than 13 percent year-to-date.
Exxon Mobil reported quarterly earnings and revenue that beat analysts' expectations. Shares posted a 0.4 percent gain and are up more than 13 percent for the year so far.
U.S. crude oil futures settled 11 cents lower, or 0.24 percent, at $45.92 a barrel after topping $46 Thursday for its highest close since early November. The weekly oil rig count showed a sixth-straight week of decline.
WTI notched its first three-month win streak since 2013 with a 19.77 percent gain in April. However, the commodity is still in bear market territory, off more than 20 percent from its 52-week intraday high.
"The price of crude oil has gotten completely detached from fundamental levels," Roberts said. "There's a bit of a detachment from oil prices in the market right now."
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In economic news, personal spending rose 0.1 percent in March, while personal income rose 0.4 percent. The Employment Cost Index, the broadest measure of labor costs, increased 0.6 percent after an unrevised 0.5 percent gain in the fourth quarter, the Labor Department said on Friday.
The Fed's preferred inflation measure, the ex-food and energy personal consumption expenditures (PCE) price index, edged up 0.1 percent last month. In the 12 months through March, the core PCE rose 1.6 percent after advancing 1.7 percent in February.
Treasury yields were mixed, with the 2-year yield near 0.78 percent and the 10-year yield around 1.83 percent.
"A little bit of a volatile day," said Guy LeBas, chief fixed income strategist at Janney Montgomery Scott.
"I think we're following equities a bit in the final trading hours," he said.
The Federal Reserve could raise U.S. interest rates as soon as June or July if second-quarter economic data is strong, Dallas Federal Reserve President Robert Kaplan said in a Reuters report Friday.