The Dow Jones Industrial Average finished at 15,464.07, up 3.15 points, or 0.02%. The Standard & Poor's 500 Index ended at 1,680.19, up 5.17 points, and the Nasdaq closed at 3,600.08, up 21.78 points.
Thursday, the Dow and S&P marked new milestones and the Nasdaq ended at its highest level since October 2000, egged on by dovish central bank comments.
But some analysts questioned the stellar gains.
"While you cannot guarantee that short-covering is taking place, this looks, smells and feels like a huge short covering," Art Cashin, director of floor operations at UBS Financial Services told CNBC. "Next week we have the equivalent of what used to be the Humphrey-Hawkins testimony so we could get a lot of volatility again."
Cashin is referring to the semi-annual monetary policy report Fed Chairman Ben Bernanke delivers to Congress.
Coming out Friday was the Bureau of Labor Statistics monthly producer price report, which showed a 0.8% increase in June, well above estimates ranging from 0.3%-0.5%.
A separate economic report showed U.S. consumer sentiment slipped in July as Americans grew wary about the country's recovery prospects. The Thomson Reuters/University of Michigan reading on the overall consumer confidence index fell in July to 83.9 from 84.1 in June. Analysts were looking for a gain to 84.7.
With Q2 season getting underway, earnings were a main focus Friday and flashed mixed signals.
As was the case last quarter, expectations for Q2 S&P earnings per share have continued to be trimmed heading into earnings season.
Analysts are anticipating EPS of $26.64, a 1.4% increase from the same quarter a year ago. That's well below Q1's 3% growth.
"So far just 50% of companies have beaten on EPS, 45% have beaten on sales, and 23% have beaten on both," Saviat Subramanian, head of U.S. equity and quantitative strategy at Bank of America Merrill Lynch, told the Financial Times. "Coupled with the recent deterioration in revision and guidance trends, this could portend a lower proportion of positive surprises this quarter."
Analysts looking at big-bank earnings as a sign of economic health got a nice surprise Friday when two of the country's biggest financial institutions posted healthy second-quarter earnings.
Meanwhile, a global shipping economic bellwether missed on estimates and provided a dismal outlook… here's a recap: