Mr. Redleaf bought several large grain elevator complexes from ConAgra and Cargill last year for a long-term stake in what he sees as a high-growth business. The elevators can store 36 million bushels of grain.

Image Andrew J. Redleaf, head of the hedge fund Whitebox Advisors, bought several grain elevators from ConAgra and Cargill. Credit... Ben Garvin for The New York Times

“We discovered that our lease customers, major food company types, are really happy to see us, because they are apt to see Cargill and ConAgra as competitors,” he said.

The executives making such bets say that fears about their new role are unfounded, and that their investments will be a plus for farming and, ultimately, for consumers.

“The world is asking for more food, more energy. You see a huge demand,” said Axel Hinsch, chief executive of Calyx Agro, a division of the giant Louis Dreyfus Commodities, which is buying tens of thousands of acres of cropland in Brazil with the backing of big institutional investors, including AIG Investments.

“What this new investment will buy is more technology,” Mr. Hinsch said. “We will be helping to accelerate the development of infrastructure, and the consumer will benefit because there will be more supply.”

Financial investors also can provide grain elevator operators the money they need to weather today’s more volatile commodity markets. When wild swings in prices become common, as they are now, elevator operators have to put up more cash to lock in future prices. John Duryea, co-portfolio manager of the Ospraie Special Opportunity Fund, is buying 66 grain elevators with a total capacity of 110 million bushels from ConAgra for $2.1 billion. The deal, expected to close by the end of June, also will give Ospraie a stake in 57 fertilizer distribution centers and the barges and ships necessary to keep them supplied with low-cost imports.

Maintaining these essential services “helps bring costs down to the farmers,” Mr. Duryea said. “That has to help mitigate the price increases for crops.”