The Dow Jones industrial average picked up 40.89 points to 9,204.11, and the Nasdaq advanced 18.58 points to 1,671.30. CNET's technology indexes saw slight gains, with the exception of communications services, Internet e-tailers, server hardware and wireless.
Despite a note of caution from Microsoft, Wall Street was encouraged by this week's round of quarterly reports, observers said.
"Earnings are looking good. Companies are doing better, for the most part, than many people thought," said William Rutherford, chief executive of Rutherford Investment Management.
Two economic reports indicated inflation is inching up while the trade deficit shrinks.
The Labor Department reported that the Consumer Price Index--the broadest available gauge of national inflation--rose at a stronger-than-expected 0.4 percent rate last month after a 0.1 percent August gain. Wall Street had expected a gain of 0.3 percent. The stronger-than-expected gain was attributed to a spike in gasoline prices in September.
However, excluding food and energy, consumer prices climbed just 0.2 percent, the same rate as in July and also in August, indicating only mild inflation.
A report from the Commerce Department showed that the U.S. trade deficit shrank slightly in August to $27.1 billion, as exports increased and imports continued to decline during the last full month before the Sept. 11 attacks on the United States. Exports totaled nearly $84.46 billion, up $900 million from July, as shipments to China hit a record $1.92 billion.
Microsoft, down $1.15 to $57.90, on Thursday evening reported strong sales despite the tough environment for the PC industry.
Sun Microsystems shed 5 cents to $8.83 after posting a quarterly loss Thursday that met the companies' lowered estimates but topped analysts' expectations.
eBay fell $7.11 to $51.95 after news Thursday evening that revenue for its third quarter jumped around 70 percent to $194 million and its earnings topped estimates.
Nokia posted its third-quarter results Friday morning. The mobile phone maker reported a steep drop in third-quarter profit but forecast strong earnings during the fourth quarter. Shares were up $1.32 to $20.10.
Among other actively traded shares, Intel gained 10 cents to $24.15; Oracle fell 28 cents to $14.54; and Cisco Systems was unchanged at $16.72.
AOL Time Warner gained $1.27 to $31.17. Yahoo increased 10 cents to $11.37, and Amazon.com was down 46 cents to $8.01.
Staff and Reuters contributed to this report.