Alto Ingredients, Inc. (ALTO Quick QuoteALTO - Free Report) and Green Plains Inc. (GPRE Quick QuoteGPRE - Free Report) are notable participants in the U.S. biofuels and biorefining industry, with operations built around processing corn into ethanol and other value-added products. Alto Ingredients has broadened its portfolio toward specialty alcohols and essential ingredients serving food, beverage, pharmaceutical and industrial markets, while Green Plains has been reshaping the business around low-carbon fuels, renewable corn oil and higher-value protein ingredients.

The comparison between ALTO and GPRE is timely as ethanol producers contend with fluctuating corn costs, changing fuel margins and evolving renewable-energy policies. Although both companies operate under similar industry conditions, their strategic priorities differ, giving investors a useful way to assess which business is better positioned for margin improvement, earnings growth and long-term opportunities in the transition toward lower-carbon fuels.

Let's discuss in detail.

The Case for Alto Ingredients Stock

Alto Ingredients operates a diversified production platform spanning renewable fuels, specialty alcohols and essential ingredients, serving customers across health and beauty, food and beverage, industrial, agricultural and renewable-fuel markets. In the second quarter of 2026, the company posted its fourth consecutive quarter of positive gross profit, operating income, net income and adjusted EBITDA, while selling 88.5 million gallons of ethanol and specialty alcohols. 

The company is also focusing on high-return capacity and efficiency projects. During the quarter, it completed a Pekin dry-mill debottlenecking project expected to raise annual production capacity by about 8%, or 5 million gallons. Management also expects at least 90 million gallons of qualifying 2026 production to support a minimum of $15 million in net Section 45Z tax-credit income after monetization costs. 

However, Alto Ingredients continues to face headwinds in the export business. Geopolitical disruptions in the Middle East increased freight costs and reduced certainty of vessel availability, while compression in the U.S.-to-Europe arbitrage increased the competitiveness of Brazilian ethanol exports into Europe. These factors contributed to lower renewable-fuel export volumes from the year-ago period, prompting Alto Ingredients to shift more production toward the stronger domestic fuel-grade ethanol market. 

The company also incurred higher operating expenses during the quarter, partially offsetting the benefit of stronger industry conditions. Repairs and maintenance expenses increased approximately $2 million year over year, reflecting the Pekin dry mill and ICP spring outages and continued work at the Carbonic facility. SG&A expenses rose $1.8 million, partly due to performance compensation accruals and the absence of a prior-year one-time gain.

The Case for Green Plains Stock

Green Plains operates a biorefining platform centered on ethanol, distillers grains, Ultra-High Protein, renewable corn oil and carbon capture, with eight operating ethanol plants. In the second quarter of 2026, Green Plains sold 160.7 million gallons of ethanol, while its eight operating ethanol plants ran at 88% utilization. Its scale across ethanol production, carbon capture and value-added coproducts gives Green Plains a broad operating presence across the biofuels and agricultural-products markets.

Green Plains is focusing on operational excellence, lower carbon intensity and higher-value coproducts. In the second quarter of 2026, 45Z production tax credits contributed $58.7 million to adjusted EBITDA, net of discounts and other costs. The company is also using benchmarking, process chemistry and targeted technology upgrades to improve yields and efficiency across its operating network.

However, Green Plains reported lower revenues and production volumes in the second quarter of 2026. Revenues fell 19.3% year over year to $446.2 million, primarily reflecting lower ethanol volumes following the Obion, Tennessee, plant disposition. Ethanol volumes sold declined 17% to 160.7 million gallons, while total debt stood at $483.7 million and cash and restricted cash totaled $243.1 million.

Green Plains also remains exposed to seasonal demand and commodity volatility. Management expects lower driving demand to create normal seasonal pressure later in 2026, while U.S. ethanol exports must remain competitive with Brazil. Corn prices have been volatile, corn oil prices were supported by renewable-diesel demand and distillers-grain values were trending lower in the third quarter due to seasonal factors.

Valuation & Price Performance of ALTO & GPRE

Alto Ingredients currently trades at a forward price-to-sales ratio of 0.31, representing a discount to Green Plains, which trades at 0.54.

P/S Ratio (Forward 12 Months)

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Over the past month, Alto Ingredients and Green Plains have declined 11.3% and 10.9%, respectively.

One Month Price Performance

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Bottom Line

Alto Ingredients appears to have a slight edge over Green Plains, supported by its lower forward price-to-sales multiple, improving profitability and targeted capacity investments. The expected contribution from Section 45Z tax credits also provides additional earnings support. However, ALTO still faces export-market uncertainty, higher operating costs and commodity-related risks. GPRE, meanwhile, benefits from scale and value-added products but is contending with lower volumes and a sizable debt load. With both ALTO and GPRE stocks carrying a Zacks Rank #4 (Sell), caution remains warranted, though the former looks relatively better positioned. 

You can see the complete list of today’s Zacks #1 Rank (Strong Buy) stocks here.