The concluded Tuesday its longest stretch ever without back-to-back declines of at least half a percent.

The broad index went 310 trading days without consecutive pullbacks of that magnitude, before falling 0.7 percent on Monday and 1 percent on Tuesday, according to data from Bespoke Investment Group.

"Translation — bulls have been spoiled," Paul Hickey, the company's co-founder, said in a note Tuesday.

Source: Bespoke Investment Group

Stock investors had enjoyed an unprecedented period of low market volatility prior to this sell-off. The Cboe Volatility index (VIX), widely considered the best gauge of fear in the market, closed below 10 more than 50 times last year. It also failed to break above 20 at any time in 2017.

Equities have been under pressure during the past two days as fears of rising inflation pushed the U.S. 10-year yield to its highest levels since 2014, thus giving investors pause about the market's rally.

Several strategists have also begun calling for a pullback. Last week, Stifel strategist Barry Bannister predicted the Federal Reserve will cause a correction this quarter as it leads other central banks into tighter monetary policy. Meanwhile, a Goldman Sachs strategist said Monday there is a "high probability" the stock market experiences a correction in the coming months.

Equities had kicked off 2018 with a bang. The S&P 500 had risen 7.5 percent prior to this week's pullback. The index remains up 5.7 percent for the young year.