The Nasdaq got a boost from Apple, its biggest component, which gained $7.28, or 1.1 percent, to $644.82. Apple's seven-for-one stock split will happen after the close of business Friday. At the current price, Apple's new shares would be worth $92.12 after the split takes effect on Monday.
Once again trading was quiet, with roughly 2.8 billion shares changing hands on the New York Stock Exchange, compared with the recent average of 3.3 billion shares. Volume has been under 3 billion shares every day this week.
This week's main events come Thursday and Friday.
Policymakers from Europe's central bank will meet Thursday to decide whether or not to lower the eurozone's key interest rate to below zero in an effort to further stimulate Europe's economy.
The unusual move would mean banks would have to pay to park money with the European Central Bank. The goal is to push banks to lend the money to companies and individual borrowers.
While the eurozone pulled out of an 18-month recession last year, growth remains sluggish and inflation is low. Eurozone inflation was 0.7 percent in May, well below ECB's target of 2 percent.
"Europe is barely growing, inflation is low, and it cries out for more stimulus," said Bob Doll, chief equity strategist at Nuveen Investments. "The question is: Will the ECB do enough to satisfy investors?"
Speculation over the ECB's interest rate decision has sent foreign buyers into the U.S. bond market in recent weeks. The yield on the 10-year Treasury note was little changed at 2.60 percent. It went as low as 2.44 percent last week, the lowest level in almost a year.
Investors also waiting for the monthly jobs report from the U.S. Labor Department, out Friday.
Economists believe U.S. employers added 220,000 jobs in May and the unemployment rate remained steady at 6.3 percent.
Payroll processor ADP said Wednesday that U.S. businesses slowed their hiring last month, adding just 179,000 workers to their payrolls. It was the weakest hiring in four months and well below what economists had expected.
"Just when investors were getting comfortable with the positive data trend, the U.S. economy hands them a monkey wrench," said Doug Cote, chief market strategist for Voya Investment Management, in a note to investors.
In company news:
— Protective Life jumped $10.64, or 18 percent, to $69.36 after Japanese insurance company Dai-ichi Life said it would buy the company for $70 a share, or $5.7 billion.
— First Solar rose $2.46 or 4 percent, to $65.39 after the company announced it was buying German electric power operator Skytron Energy for an undisclosed amount.