With the price of crude oil falling by almost 60% since its high in 2014, we decided to check TheStreet Quant Ratings for oil companies that would be good investments. We narrowed the search down to large-cap oil refiners. Refiners do very well when the price of crude is low. Low prices means they can refine more oil, so, apart from the initial hit on inventory, future profit opportunities are strong. People also tend to buy more gas when oil is low, so there's more demand for the refineries. Here are some of the best oil refiners TheStreet Quant Ratings says you should consider looking at. Number 4 is Marathon Petroleum. With an 'A' rating, the company's strengths can be seen in its solid stocks price performance and attractive valuation levels. 3rd is, Phillips 66. This rating is also an 'A.' Phillips 66 thrives in its increase in net income and notable return on equity. 2nd is Tesoro Corporation. With an 'A+' rating the company flourishes in its attractive valuation levels and solid stock price performance. Number 1 is Valero Energy. The company's strengths can be seen in its notable return on equity and solid stock price performance. TheStreet Ratings are algorithmic stock picks based on 32 major data points. S&P 500 stocks rated 'buy' yielded a 16-and-a-half-percent return in 2014, beating the S&P 500 Total Return Index by more than 300 basis points. For the full reports on these stocks, you can check out TheStreet.com/QuantRatings.