Today marked the third-straight day that the broad-based S&P 500 (SNPINDEX:^GSPC) sat on its hands waiting for a number of key economic reports due out later in the week.

The one report that investors appeared to latch onto today, which held down the iconic S&P 500 throughout much of the session, was the weekly loan originations report from the Mortgage Brokers Association. The MBA noted that weekly mortgage originations dipped 2.1%, which isn't a huge surprise given that it rose by 9.4% last week. Overall, though, consumers have been incredibly stingy when it comes to refinancing their homes and taking on mortgages with rates well off their lows of last May, but still well below their historic average. If lending rates rise much further, it's quite possible that the housing and banking sectors could see negative repercussions.

Beyond this tidbit of economic data, geopolitical tension between Russia and Ukraine continued to weigh on the markets. Any conflict in this region has the potential to cripple growth in Russia's fast-paced economy, and could rapidly cool global growth prospects.

By day's end, the S&P 500 somehow managed to claw its way to a fractional gain of 0.57 points (0.03%), reversing yesterday's loss, to finish at 1,868.20.

Despite ending the day in the red, shares of oil and gas exploration and production company EPL Oil & Gas (NYSE: EPL) were decisively in the black, gaining 28.8% after Energy XXI (NASDAQ: EXXI) agreed to acquire the company for what amounts to approximately $1.53 billion. Under the terms of the deal, EPL shareholders can choose to either receive $39 in cash, 1.669 common shares of Energy XXI for each share they own of EPL, or some combination of the two. The merger, if approved, is going to create the largest publicly owned independent oil producer in the Gulf of Mexico shelf, with production of approximately 65,000 barrels of oil equivalent per day. The move should also work to diversify its field assets and improve cost synergies, as well as be immediately accretive to Energy XXI's bottom line. Despite the uncertainty surrounding E&P drillers in the Gulf at the moment, I see this as a smart move for Energy XXI, and would consider today's dip a possible buying opportunity.

Shares of optical transport networking equipment maker Infinera (NASDAQ:INFN) gained 14.9% after research firm Goldman Sachs upgraded the company to buy from neutral, and introduced a price target of $11.50, implying a 36% premium from yesterday's close. The move was made in anticipation of a margin upswing due to the adoption of 100G optical components. Considering how much domestic telecom providers are spending to improve their infrastructure, better results from Infinera were expected by me sooner rather than later. The company has also trounced Wall Street's EPS estimates in each of the past four quarters. However, at 33 times forward earnings, and with a growth rate in the low teens, I'd consider waiting for a sizable pullback before considering a purchase of Infinera.

Finally, highly volatile fuel-cell systems developer Plug Power (NASDAQ:PLUG) advanced 12.8% after collapsing more than 40% yesterday following negative commentary from Citron Research and chief researcher, Andrew Left. In a report released later in the day yesterday, Left noted that the fair valuation of Plug Power should be about $0.50 given its lack of profitability. As a reminder, all of this volatility stems from the bullishness surrounding a 1,738 fuel-cell system order to power forklifts in six regional warehouses for Wal-Mart. As I've said previously, while I do believe this a big order for Plug Power, and it could go a long way to validating the long-term use of the technology, its order history remains lumpy, and profitability will likely be hit-and-miss, at best. With that being said, I'd suggest sticking to the sidelines.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.