Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

Not to sound like a broken record, but the S&P 500 (SNPINDEX:^GSPC) again roared to a record high following another day of positive economic data and better-than-expected profits.

On the economic data front, weekly initial jobless claims dropped modestly by a seasonally adjusted 2,000 to 339,000, which signals to investors that the jobs market is slowly improving and that fewer people are having trouble finding work.

In addition, Federal Reserve chair nominee Janet Yellen excited the market with statements in front of the U.S. Senate Banking Committee that the economy is significantly stronger than many had forecast. Many economists believe there's a good likelihood that targeted federal funds rates could remain near zero for perhaps three or four more years under Yellen, which would be beneficial for consumer spending and industries like the housing sector.

By day's end the S&P 500 had digested all of this data and commentary, sending the iconic index up 8.62 points, 0.48%, to another all-time closing high of 1,790.62.

Standing above all other S&P 500 components today was information management services company Iron Mountain (NYSE:IRM) which gained 7.7% on the day despite no company-specific news. Iron Mountain has been particularly volatile over the past year while being delayed in its attempts to convert to a real estate investment trust. Investors would love to see that happen because it would mean at least 90% of Iron Mountain's earned income would need to be returned to shareholders in the form of a dividend. Likewise, Iron Mountain would get preferential tax treatment as a REIT. Key to whether the company will be able to convert is how certain aspects of Iron Mountain's business are classified.

In similar fashion, oil refiner and marketer Marathon Petroleum (NYSE:MPC) advanced 5% despite having nothing in the news column. What really appeared to drive shares higher today is a lower crude oil price, which helps improve demand for oil (and thus refining) and can occasionally improve the crack spreads on which refiners make their profits. However, refining revenue and earnings per share for Marathon have been on a steep downtrend over the past three months. I'm not certain they'll reverse course so quickly even with oil prices well off their recent highs. Marathon Petroleum is a name I'd add to your watchlist, but not a company I'd consider an attractive investment yet.

Finally -- and continuing our theme of newsless moves -- PulteGroup (NYSE:PHM) moved higher by 4.9% after reacting to the positive commentary made by Yellen. Homebuilders are particularly sensitive to interest rate increases, so the recent downtrend in lending rates coupled with speculation that Yellen would continue to target a federal funds rate near zero for years to come is viewed as a growth driver for the housing industry. I would still advise a bit of caution on Pulte given that even the slightest nudge higher in lending rates has been enough to drive down the weekly loan originations measure from the Mortgage Brokers Association.

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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