Why Marathon Petroleum, Dollar General, and Teradata Tumbled Last Week

The S&P 500 didn't manage to make more gains last week, but it didn't fall too far, either, with a drop of just a couple of points reassuring many that the stock market is still in prime position to rebound and reach new record levels in the near future. Yet downward pressure from many stocks within the S&P 500 contributed to the week's losses, and Marathon Petroleum , Dollar General , and Teradata were among the worst performers in the index.

Source: Marathon Petroleum.

Marathon Petroleum's 11% loss came amid substantial drops throughout the refining industry as the company came to grips with a U.S. Department of Commerce decision allowing two companies to export a form of condensate, or what many are calling ultra-light crude oil. Many investors panicked at the outset, figuring that the decision signaled a huge change in U.S. trade policy that would eventually open the floodgates to wholesale export of all types of U.S.-produced crude and therefore eliminate the cost advantage for domestic crude that Marathon Petroleum and its peers have taken advantage of for years. Yet it's far from clear that the Commerce Department decision is anything other than a short-term response to current conditions in the domestic oil and gas market, and even in a worst-case scenario, Marathon Petroleum should be able to adapt to limit any damage to its margins in the long run.

Source: Dollar General.

Dollar General fell 9% as investors reassessed the likelihood of a merger with one of its major peers in the dollar-store industry in light of the resignation of CEO Richard Dreiling. Activist investor Carl Icahn has argued that consolidation in the dollar-store arena is necessary to help companies eliminate cannibalizing each other's business opportunities and to eliminate duplicated costs. Yet with Dreiling leaving the company, Dollar General will have to focus its efforts on finding a replacement chief executive to lead the company forward. Unless that search leads Dollar General toward exactly the merger Icahn has in mind, any merger efforts might get put on the back burner until the top-spot situation gets resolved.

Teradata dropped 8% in a steady weeklong decline. Early in the week, an analyst downgrade raised questions about whether the data warehousing and analytics provider will be able to deal with competition from other service providers in the industry. In particular, Hadoop and other companies using more comprehensive open-source solutions represent a threat to Teradata, with some customers pointing to cost advantages from using Teradata's competitors. For its part, Teradata released a tool this week that improved the performance of certain open-source analytics platforms, but the company has to do more to keep its overall growth rate moving in the right direction.

Leaked: Apple's next smart device (warning -- it may shock you)
Apple recently recruited a secret-development "dream team" to guarantee that its newest smart device was kept hidden from the public for as long as possible. But the secret is out, and some early viewers are even claiming that its everyday impact could trump the iPod, iPhone, and the iPad. In fact, ABI Research predicts that 485 million of these devices will be sold per year. But one small company makes this gadget possible. And its stock price has nearly unlimited room to run for early in-the-know investors. To be one of them, and to see Apple's newest smart gizmo, just click here!

The article Why Marathon Petroleum, Dollar General, and Teradata Tumbled Last Week originally appeared on Fool.com.

Dan Caplinger and the Motley Fool own shares of Apple. The Motley Fool recommends Apple and Teradata. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.

Copyright © 1995 - 2014 The Motley Fool, LLC. All rights reserved. The Motley Fool has a disclosure policy.

Read Full Story