Key Takeaways

Major U.S. equities indexes were mixed on Wednesday as the latest Consumer Price Index (CPI) data showed an unexpected uptick in inflation during January.

The S&P 500 slipped 0.3%. The Dow ended the session 0.5% lower, while the Nasdaq eked out a minimal gain of less than 0.1%.

Westinghouse Air Brake Technologies ( WAB ) shares dropped 9.1%, falling the most of any S&P 500 stock. The manufacturer of products for locomotives and railroad systems missed quarterly sales and profit forecasts. The company, commonly known as Wabtec, also issued lower-than-expected full-year earnings guidance, citing pressure on freight demand along with increased prices and borrowing costs.

Arista Networks ( ANET ) shares lost 6.2% following reports that the cloud networking firm's chief technology officer recently sold a significant stake in the company. Investors often view sales by company insiders as a possible warning signal about a stock's upcoming performance. Wednesday's downturn reversed a portion of strong gains posted by Arista stock over the past two weeks, boosted by expectations of robust demand for scalable cloud networking infrastructure.

Waters ( WAT ), which provides analytical instruments and software for scientific research laboratories, edged out fourth-quarter sales and profit expectations, but its first-quarter guidance came in below expectations. The company noted a negative impact from currency exchange as the strength of the U.S. dollar pressures its international revenue. Waters shares tumbled 5.8% on Wednesday.

The top performance in the S&P 500 Wednesday came from shares of CVS Health ( CVS ), which surged 14.9% after the pharmacy operator and health insurance provider topped fourth-quarter sales and profit estimates . CEO David Joyner, who took the reigns of CVS amid a strategic reshuffling in October, noted strong growth in the pharmacy and consumer wellness business as the company navigates a challenging environment in the health care benefits segment.

Shares of Generac Holdings ( GNRC ) were 7.6% higher after the provider of portable, residential, and commercial generators outperformed profit expectations with its fourth-quarter results. The company noted that declining power quality and increasing prices, as well as the prevalence of extreme weather and power outages, contributed to strong demand.