Stocks fall on the open as the busiest week of earnings season kicks off

Halliburton and Kimberly-Clark are among the companies that reported better than expected quarterly results on Monday morning. Their shares rose 1.6% and 5.3% respectively.

So far, the majority of company revenue has reported topped expectations. FactSet data show that 76.5% of the S&P 500 companies that have entered revenues have exceeded analysts' estimates. Analysts entered the season with low season expectations, forecasting a 4.2% decline in profits.

"Considering the bar has been set very low for the first quarter profit, the likelihood of any surprises being upside down," said Bruce Bittles, chief investment strategist at Baird, in a note. "Historically, the shares have done the best when the earnings gains have been modest in contrast to when earnings growth has been strong."

The broader market also fell after South China Morning Post reported that China's political committee would pursue structural changes in its economy, rather than adding stimulus. Chinese stocks closed sharply during the night, while the Shanghai Composite lost 1[ads1].7%, while the Shenzhen A Shares index fell 1.5%.

Wall Street also focused on the oil market while US crude rose 2.2% after the Trump administration said it would not allow the purchase of Iranian oil by some countries. The move can take about 1 million barrels a day out of the oil market. Energy shares increased along with oil prices. Energy Select Sector SPDR Fund (XLE) traded 1% higher, led by Marathon Oil and Apache.

On the data front, existing housing sales are expected for March at 10.00 ET.

CNBCs Holly Ellyatt contributed to this report.