U.S. stock index futures fell on Friday as investors locked in gains at the end of a strong quarter for equities and amid uncertainty ahead of the result of stress tests on Spanish banks.
A plan for economic reform in Spain had sparked a rally Thursday, though the bank stress-test results and a review of Spain's credit rating by Moody's, both due later in the day, could compound the nation's challenges in dealing with its debt.
Trading was light as investors were reluctant to make big moves following Thursday's gains and on the last day of the quarter, when money managers reposition their portfolios. The S&P has advanced 6.2 percent over the past three months.
"On this last day of the quarter, the focus remains on the situation in Europe, which is causing nervousness and could result in a sell-off," said Peter Cardillo, chief market economist at Rockwell Global Capital in New York. "We'll probably see a mixed session today, though we'll cling to the gains we saw in the quarter."
In company news, Nike Inc reported first-quarter earnings late Thursday that beat expectations, though it warned of slowing orders in China, the latest company to caution on how economic weakness in the Asian giant was impacting its business. Shares fell 3.3 percent in light premarket trading.
U.S. shares of Research in Motion rocketed 16 percent to $8.26 in premarket trading after the BlackBerry maker reported a smaller-than-expected quarterly loss.
S&P 500 futures fell 5 points and were below fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures lost 52 points and Nasdaq 100 futures sank 7.5 points.
The S&P is down 0.9 percent this week so far, for a second straight week in the red, though Thursday's rally sharply narrowed the losses from five straight days of declines. The Dow is down 0.7 percent for the week and the Nasdaq is down 1.4 percent.
Wall Street's gains in the quarter were largely linked to expectations for measures by central banks around the world to boost their economies.
After those expectations were met, stocks have struggled for direction and trading has been thin, as investors looked to new catalysts amid lackluster data and lowered corporate earnings outlooks. Advance Micro Devices , which cut its outlook in July, has slumped 40 percent to be the S&P's worst performer this quarter.
Investors are looking ahead to August personal income and consumption data at 8:30 a.m. ET (1230 GMT). The Institute of Supply Management Chicago's September manufacturing activity index will be released later, as will the final September read of the Thomson Reuters-University of Michigan consumer sentiment index.
Income and spending are seen rising modestly while the ISM index is seen holding steady at 53 and the sentiment index is seen moving to 79 from 79.2 in the preliminary report.
"The economy is quite sluggish, as we've seen in recent data," Cardillo said. "That will probably continue for the rest of the year."
There may be volatility on Friday as investors "window dress," or undergo a last-minute push to reposition portfolios ahead of the quarter's end. MetroPCS and Sprint Nextel are the S&P's two biggest gainers in the quarter, with the former almost doubling in value.
The S&P snapped a five-day losing streak on Thursday, climbing 1 percent in its best daily gain since the Federal Reserved announced a new program of monetary easing September 13. The rally came on Spain's reform plan and overshadowed a weak read on gross domestic product and durable goods.
(Editing by Bernadette Baum)