The Dow Jones Industrial Average was up 11.06 points, or 0.04 percent, to 26,554.39. The S&P 500 rose 3.15 points, or 0.11 percent, to 2,943.03. The Nasdaq Composite Index increased 15.46 points, or 0.19 percent, to 8,161.85.
Of the 11 primary S&P 500 sectors, financials and communications outperformed while real estate and utilities underperformed.
About 150 S&P 500 companies are scheduled to report their quarterly results this week, including U.S. tech giants Apple and Qualcomm.
Google-parent Alphabet reported earnings results after Monday's close. The stock fell more than 6 percent in afterhours trading shortly after the company delivered disappointing quarterly revenue.
Of the S&P 500 companies that have reported quarterly results so far, about 77.5 percent have topped analyst expectations, according to data from FactSet.
On the economic front, U.S. personal income rose 0.1 percent in March, following a 0.2-percent increase in February, according to estimates released Monday by the Bureau of Economic Analysis.
The personal consumption expenditures increased 0.9 percent in March, said the report.
Economists surveyed by MarketWatch had been expecting a 0.8-percent gain in consumer spending and a 0.4-percent gain in income.