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What: Shares of rendering and renewable diesel company Darling Ingredients (NYSE:DAR) rose 10% last month, after gaining a whopping 46% in March on the heels of impressive 2015 financial performance. This time the catalyst was a 15% rise in oil prices.

So what: Darling Ingredients' operations are heavily tied to oil prices, both (1) indirectly through trickle-down pricing effects on the commodity food and feed ingredients it sells and (2) directly through fuel ingredients and fuels. While the company's fuel ingredients segment accounted for only 7% of total revenue in 2015, its share of net income from the Diamond Green Diesel joint venture alone would have accounted for 27% of the total from its three business segments. Despite the recent turmoil in oil prices, renewable diesel represents an important growth avenue for investors.

The importance will only continue to grow. On April 7, Darling Ingredients announced plans to expand the nameplate capacity of the Diamond Green Diesel joint venture from 160 million gallons per year to 275 million by 2018.

Now what: I don't think one month of oil price movements in any direction should be enough to warrant much of a reaction from Darling Ingredients investors. Instead, focus on the health of the company, which appears to be excellent. Management's ability to keep costs down, continue growing and acquiring businesses in high-value and high-growth markets, and focus on the long-term viability of the business will be -- and has been -- a crucial advantage to investors when headwinds arise in commodity markets.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.