The marketsgave back all of Monday's gains today with all of the major indices closing near their lows. The Dow 30 sold off 136 (-0.76%), the S&P 500 closed off 18 (-0.86%), and the Nasdaq 100 closed lower by a whopping 54 (-1.13%) despite Apple (AAPL  ) holding in the green.

Pfizer (PFE  ) made headlines early today as the pharmaceutical giant topped Wall Street estimates in the first quarter and raised its full year revenue and earnings forecast. Pfizer reported adjusted earnings per share of $0.67 on revenue of $13.01 billion. This caused a strong gap higher today and a nice close of 2.74%. Today's close marks new 2016 highs for Pfizer.

General Motors (GM  ) wasn't so lucky today. The auto giant lost 1.61% as U.S. sales fell 3.5% in the month of April due to a decline in fleet business. But, the company tried to highlight that its retail sales rose 3.3%, boosted by sales at its Chevrolet, Buick, and GMC brands.

In "to be a kid again" news, Six Flags (SIX  )  released plans for its new theme park in Dubai. Six Flags' new theme park scheduled to be opened in 2019 and will include "record-breaking" roller coasters. Investors we unable to support the, already extended stock today, and shares lost 1.51%.

Back to earnings releases, Sprint (S  ) popped 5.16% today as the wireless carrier reported better-than-expected fourth-quarter earnings. Sprint is in the middle of a multi-year plan to transform the way it does business and significantly lower costs.

Lastly, Yelp (YELP  ) popped 2.98% today as hedge fund manager David Einhorn revealed that he has made new investments in the business review site. In his first-quarter letter to investors, Einhorn wrote, "If the company executes its current plan, by 2019 it will double revenues and earn $300 million of EBITDA at a 35% margin." Technical traders also took note of the short term breakout, and volume was heavy.