NEW YORK (TheStreet) -- Shares of Valero Energy Corp. (VLO) - Get Report are falling by 5.33% to $58.40 on heavy volume in late afternoon trading on Monday, as some stocks within the energy and oil sectors slump today along with the price of the commodity.

Brent crude is down by 4.63% to $59.68 per barrel and WTI crude oil is lower by 0.26% to $49.63 per barrel, reversing earlier gains, according to the CNBC.com index.

Brent is slipping today following statements from Iran saying it is close to agreeing on a deal regarding its nuclear program. An agreement could be reached as early as this week if the West were to lift sanctions on the country, which could end up increasing Iran's oil exports, Reuters reports.

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A stronger dollar and reports that Libya's crude output increased are also weighing on oil.

"If there is the political will to accept that an agreement and sanctions cannot go together, then we can have an agreement at this time," Iranian Foreign Minister Javad Zarif said, Reuters added.

Other oil and energy related stocks moving lower today include Marathon Petroleum Corp. (MPC) - Get Report, down by 3.38% to $101.45, Chevron Corp. (CVX) - Get Report, down by 1% to $105.61, and Anadarko Petroleum Corp. (APC) - Get Report lower by 2.96% to $81.74 this afternoon.

Separately, TheStreet Ratings team rates VALERO ENERGY CORP as a Buy with a ratings score of A-. TheStreet Ratings Team has this to say about their recommendation:

"We rate VALERO ENERGY CORP (VLO) a BUY. This is based on the convergence of positive investment measures, which should help this stock outperform the majority of stocks that we rate. The company's strengths can be seen in multiple areas, such as its largely solid financial position with reasonable debt levels by most measures, attractive valuation levels, notable return on equity and solid stock price performance. We feel these strengths outweigh the fact that the company shows low profit margins."

Highlights from the analysis by TheStreet Ratings Team goes as follows:

• VLO's debt-to-equity ratio is very low at 0.28 and is currently below that of the industry average, implying that there has been very successful management of debt levels.
• The return on equity has improved slightly when compared to the same quarter one year prior. This can be construed as a modest strength in the organization. Compared to other companies in the Oil, Gas & Consumable Fuels industry and the overall market on the basis of return on equity, VALERO ENERGY CORP has underperformed in comparison with the industry average, but has exceeded that of the S&P 500.
• Looking at where the stock is today compared to one year ago, we find that it is not only higher, but it has also clearly outperformed the rise in the S&P 500 over the same period, despite the company's weak earnings results. Turning our attention to the future direction of the stock, it goes without saying that even the best stocks can fall in an overall down market. However, in any other environment, this stock still has good upside potential despite the fact that it has already risen in the past year.
• VLO, with its decline in revenue, slightly underperformed the industry average of 18.7%. Since the same quarter one year prior, revenues fell by 19.1%. Weakness in the company's revenue seems to have hurt the bottom line, decreasing earnings per share.
• You can view the full analysis from the report here: VLO Ratings Report