Closely watched consumer pricing data, often viewed as an inflation barometer, rose 0.2 percent in May, matching expectations. In the 12 months through May, the CPI increased 2.8 percent, the biggest advance since February 2012, after rising 2.5 percent in April.
A slowdown in the climb of gasoline prices helped dampen the movement upward, though core CPI, which excludes volatile food and energy costs, also rose 0.2 percent. The year-over-year increase in core CPI is now 2.2 percent.
Investors also digested the latest news out of a historic meeting between the leaders of North Korea and the U.S. in Singapore.
Following weeks of anticipation, President Donald Trump and North Korean leader Kim Jong Un met in the city-state of Singapore, which saw Kim sign an accord that "reaffirmed his firm and unwavering commitment to complete denuclearization of the Korean Peninsula."
While the news appears reassuring, investors remain on edge as to what each country will see as "complete denuclearization." Following the meeting, Trump stated that the Korean conflict would end shortly, adding that both leaders learned a lot about one another.
With investors still cautious as to what the future of talks between North Korea and the West will look like, markets around the world fluctuated, with Europe trading flat while stocks in Asia closed mostly in the black.
The U.S. Treasury meantime will auction $14 billion in 30-year bonds.
Elsewhere, investors will be turning their attention to the start of a new monetary policy meeting by the U.S. Federal Reserve. Tuesday will mark the first day of June's two-day policy meeting, where investors expect the U.S. central bank to announce a quarter-point increase in interest rates.
Following this event, which is expected to draw to a close on Wednesday afternoon, the European Central Bank will host its next monetary policy meeting on Thursday.
—CNBC's Nyshka Chandran and Everett Rosenfeld contributed to this report.