The S&P 500 eked out a record high, but major indexes closed little changed after conflicting reports on jobless claims and the housing market.
Investors also focused on quarterly results for US corporations.
At the closing bell, the S&P 500 added 0.97 of a point, or less than 0.1%, to 1,987.98, advancing for the third day in row.
Other major stock benchmarks lost ground. The Dow Jones Industrial Average fell 2.83 points, or less than 0.1%, to 17,083.80, while the Nasdaq Composite Index fell 1.59 points, or 0.1%, to 4,472.11.
Stocks opened higher after a report showed that Americans filed the fewest applications for unemployment benefits last week since February 2006. Initial jobless claims fell to 284,000, well below expectations for 305,000.
But stocks pared gains after new-home sales fell 8.1% in June from May, well below expectations. The May reading was also revised significantly lower.
Meanwhile, early corporate reports have been mostly positive, and analysts have revised higher their estimates for earnings increases among S&P 500 companies, now expecting a gain of 5.6% versus 4.9% previously, according to FactSet.
Marc Reinganum, State Street Global Advisors' chief quantitative strategist and portfolio manager of the Dynamic Small Cap Fund, said that companies are turning out solid reports. Many are "delivering earnings growth and producing growth to match higher expectations," he said.
Facebook jumped 5.2%, notching a record high, after the social network said Wednesday its profit more than doubled and revenue topped estimates. Facebook's strong report showed that the company was successfully navigating the shift to mobile advertising as it continues to add users.
Under Armour was the leader of the S&P 500, surging 15%, after the company reported that strong footwear and apparel sales buoyed its second quarter results. It also raised its outlook for full-year sales.
Industrial stocks were the worst performers after mixed earnings in that sector.
Caterpillar fell 3.1% after earnings topped analysts' expectations, but revenue came up short. The company pointed to weaker sales in China, Africa and the Middle East and tightened the range of its revenue estimates.
Ford Motor rose 0.3% after the carmaker beat earnings expectations, reporting strength in North America, Europe and Asia. General Motors slumped 4.5% after its profit sank 80% as the automaker was hit by recalls.
Despite gains, Clifford Davis, managing director in equity derivatives at BNP Paribas, noted cautious activity from clients in recent days who have been setting up positions to protect their portfolios from declines.
"We don't have euphoria at the moment," he said. "There's a lot more positioning for a pullback than we've seen in a while."
But Kevin Blocker, senior quantitative analyst at Horizon Investments, said the strength in stocks this week is a sign of resilience after geopolitical flare-ups rattled markets last week.
"The funky nervousness and volatility has gone away this week," he said, noting that money from investors continues to stream in to buy each time the market falters. "You see demand swamp in every time."
Mr Blocker's firm's research points to continued strength in shares of large US companies and the technology sector. He is more cautious about higher-income-paying sectors including real estate and utility stocks.
The Stoxx Europe 600 rose 0.4%, buoyed by data showing that private sector activity in the eurozone expanded faster than expected in July. The composite purchasing managers index for the region rose to a three-month high of 54.
The Chinese manufacturing sector rose for the second month in a row in July, with the HSBC preliminary manufacturing PMI reaching an 18-month high. China's Shanghai Composite rose 1.3%, while Japan's Nikkei Stock Average fell 0.3%.
Qualcomm fell 6.7% after the wireless-tech company noted some worries about licensees in China, even as it lifted its full-year adjusted earnings outlook.
TripAdvisor slumped 5.2% after the online-travel website said its second-quarter profit missed the expectations of Wall Street analysts.