Today marked one of the tighter trading ranges for the S&P 500 (INDEX: ^GSPC) for the year, roughly a 6-point total swing, but it nonetheless continued its melt-up rally, tacking on exactly 3 points (0.21%) to end at 1,436.56. A German court OK'd Germany's involvement in the European bailout fund, clearing the way for much needed liquidity in some of its more troubled member nations. Apple (Nasdaq: AAPL) also stole the show today, unveiling the highly anticipated iPhone 5, which sports a bigger screen and a thinner body and has better battery life. You can get the full scoop from our in-depth live chat hosted earlier.

Now, let's take a look at some of the companies that caused the S&P 500 to tick higher and note a few of the day's underperformers.

Companies that helped the S&P 500
Homebuilder PulteGroup (NYSE: PHM) was a big winner today, rising 6%, after receiving an upgrade to "buy" from Williams Financial Group. Williams sees Pulte finally realizing the benefits of its cost-cutting strategies and growth initiatives. It also didn't hurt that newly released data from CoreLogic showed that the number of homeowners underwater on their mortgages declined slightly. My Foolish colleague Morgan Housel recently offered up 14 reasons housing may have bottomed, and this appears to be further evidence that he may be correct.

Vulcan Materials also continued its incredible run by marching higher an additional 10.7%. As I noted earlier this week, Martin Marietta has actively been pursuing Vulcan Materials with a hostile bid since December. With a court injunction that required Martin Marietta to drop its bid in May ready to expire, it once again appears that investors expect Martin Marietta to take their offer directly to shareholders.

Companies that hindered the S&P 500
On the other hand, Monster Beverage (Nasdaq: MNST) had one monster of a bad day, down 10% following a call from two U.S. senators to better regulate energy drinks. Specifically, these two Democratic senators, Richard Durbin of Illinois and Richard Blumenthal on Connecticut, question the claim that energy drinks qualify as a dietary supplement, in addition to questioning the overall safety of the drinks. As far-fetched as this idea may sound, it's an all-too-real possibility as I outlined last month.

The woes also continued for shareholders of Exelon (NYSE: EXC), who endured a downgrade by UBS to "sell" from "neutral." UBS also slashed its price target on Exelon to $31 from $37, citing the likelihood of tighter margins in the retail power business. This is one that I'm going to humbly disagree with UBS over. I see a multitude of catalysts -- including its recent merger with Constellation Energy, its alternative energy initiatives, and its nearly 6% dividend yield -- that could send Exelon much higher.

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