As we enter the heart of earnings season, the broad-based S&P 500 (SNPINDEX:^GSPC) shook off weak figures from the housing sector to end the day nicely higher.

According to the National Association of Realtors, existing home sales dipped 0.6% in March to a seasonally adjusted rate of 4.92 million, compared with estimates that had been calling for 5 million. One side of the coin would imply that housing sales are beginning to lose steam. Then again, the glass-is-half-full crowd would point out that tight supply is helping to boost the price of existing and remaining homes, which will ultimately help homebuilders' margins.

The big boost today came from a slew of earnings reports that continue to track better than expected. It's worth noting that through Friday of last week, 104 of 500 S&P 500 companies had reported earnings, with two-thirds topping estimates -- yet many more have missed Wall Street's revenue estimates, implying that cost-cutting appears to be the primary growth driver right now.

For the day, the S&P 500 finished higher by 7.25 points (0.47%) to close at 1,562.50. Here's a look at the three best performers within the index on this moderate up day.

Online streaming giant Netflix (NASDAQ:NFLX) topped the gainers in the S&P 500 today, gaining 6.7% on the heels of an analyst upgrade. Research firm B. Riley boosted its rating from "sell" to "neutral" on Netflix just hours ahead of its first-quarter earnings report. Given that international streaming growth boosted profits last quarter, investors will be keying in on streaming growth as well as expense control as the keys to a successful quarter. As for me, I stand by my assessment that the valuation here has gotten way out of hand.

Biotech behemoth Biogen Idec (NASDAQ:BIIB) continued its near-vertical ascent, advancing 5.9%, following positive comments from ISI Group analyst Mark Schoenebaum as reported by Adam Feuerstein of TheStreet.com. According to Schoenebaum, sales of Tecfidera, Biogen's new oral relapsing MS medication that drastically reduces the complications seen in competing drugs, hit sales levels in its first week that it took Novartis' (NYSE:NVS) Gilenya about three months to hit. If you recall, one of my primary contentions why Tecfidera's sales would leap that of Gilenya's had to do with Gilenya's potential to cause cardiovascular problems. I've been saying for months that Tecfidera (previously known as BG-12) was going to be a blockbuster, and if these results are accurate, it's well on its way to becoming one.

Finally, oil service and equipment company Halliburton (NYSE:HAL) jumped 5.6% after reporting better-than-expected first-quarter earnings. Although Halliburton was dragged into a GAAP loss because it was forced to set aside $637 million to a Gulf of Mexico loss reserve relating to settlement from the 2010 Gulf spill, its adjusted EPS of $0.67 and revenue of $6.97 billion easily topped estimates calling for EPS of $0.57 on revenue of $6.88 billion. Halliburton once again delivered strong international revenue growth of 21%, but it continued to experience tepid demand in the Gulf of Mexico despite rising natural gas prices. Over the weekend I labeled Halliburton as a great dividend you could buy right now and would encourage investors to drill deeper into the Halliburton story.

Fool contributor Sean Williams has no material interest in any companies mentioned in this article. You can follow him on CAPS under the screen name TMFUltraLong, track every pick he makes under the screen name TrackUltraLong, and check him out on Twitter, where he goes by the handle @TMFUltraLong.

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