NEW YORK (TheStreet) -- Shares of Marathon Oil  (MRO - Get Report) closed higher by 4.8% to $13.96 on Monday, as the price of oil climbed.

Crude oil (WTI) is rising by 2.3% to $49.74 per barrel and Brent crude is up by 1.83% to $50.55 per barrel, CNBC reports late this afternoon.

A weak dollar and supply outages in Nigeria continue to drive oil prices higher this month.

Nigeria's oil production in June is down to about 1 million barrels a day from 1.8 million a year earlier due to attacks from the country's militant forces. On Friday, bombings hit two Nigerian pipelines, Wall Street Journal reports.

"If the Nigerian output goes to zero...(prices) are going higher. At this point, there is no sign that Nigeria is getting any better, and it's looking worse," Scott Shelton, ICAP broker, says, according to the Journal.

Separately, TheStreet Ratings rated Marathon Oil as a "sell" with a score of D.

This is driven by some concerns. The company's weaknesses can be seen in multiple areas, such as its poor profit margins, weak operating cash flow, generally disappointing historical performance in the stock itself, disappointing return on equity and feeble growth in its earnings per share.

You can view the full analysis from the report here: MRO

TheStreet Ratings objectively rated this stock according to its "risk-adjusted" total return prospect over a 12-month investment horizon. Not based on the news in any given day, the rating may differ from Jim Cramer's view or that of this articles's author.