The era of Ben Bernanke is now over, and tomorrow morning the first female head of the Federal Reserve, Janet Yellen, will ring in a new era as she addresses Congress and outlines her economic mind-set. "Big Ben" stepped down as Fed chairman at the end of January, and investors around the globe are hoping that Yellen's tenure isn't fraught with the sorts of severe economic calamities that plagued Bernanke's reign. With little new data to go on and only Yellen's appearance to look forward to, the S&P 500 Index (^GSPC -0.03%) teetered through the day, ending up 2 points, or 0.2%, to end at 1,799.
Although most stocks edged higher on Monday, the oil and gas sector was the single worst-performing area of the markets, losing 0.6% as a whole. Shares of Texas-based refiner Phillips 66 (PSX 0.06%) shed 2.7% on Monday, as oil prices broke $100 a barrel. Refiners face tougher margins as the price of oil goes up, since they have to purchase oil at the higher price before refining and selling it. Phillips 66, a $42 billion company, is the largest independent oil refiner in the U.S.
Valero Energy (VLO -0.58%) is no mom-and-pop business, either, with a market cap around $25 billion. Shares lost 2.5% today, ending with Phillips 66 toward the bottom of the S&P 500. Valero Energy is also an oil refiner, so it was already facing headwinds in today's market, but the company's quarterly dividend is what really sent it southward. Valero rewards investors with a $1.00 (or 2%) dividend per share per year, which amounts to $0.25 (or 0.5%) per share per quarter. On "ex-dividend" days, like today, shares are expected to have a 0.5% downwards bias, since anyone who owned shares yesterday could've sold them today and still locked in that $0.25 quarterly dividend when it's paid out.
Lastly, shares of Marathon Petroleum (MPC -0.32%) fell 2.3% Monday, rounding out today's list of laggards. I'll give you three guesses what sector Marathon Petroleum falls under. If you guessed technology, you're out of luck, and probably a bit confused as well. Marathon Petroleum is in the oil and gas sector; specifically, it's a refiner. Like Phillips 66 and Valero Energy, higher domestic oil prices mean lower margins for Marathon, whose financial success is based, broadly speaking, on the difference between domestic and international oil prices. Marathon goes "ex-dividend" on Friday.