Glencore Plc-backed agriculture trader Viterra is in talks to merge with U.S. rival Bunge Ltd., people with knowledge of the matter said. 

The companies are discussing the structure of a potential deal, according to the people, who asked not to be identified discussing confidential information. Shares in Bunge, which has a market value of about $13.4 billion and is based just outside St. Louis, surged as much as 10 percent, the most since March.

Glencore has flirted with the idea of a deal with Bunge on and off for years, and there’s no certainty they will be able to reach an agreement on terms of a transaction, the people said. In 2017, it approached Bunge about a friendly takeover but was publicly rebuffed by the U.S. firm.

Representatives for Bunge and Glencore declined to comment, while a spokesperson for Viterra didn’t immediately provide comment.

Bunge chief executive officer Greg Heckman spent most of his tenure — which started in 2019 — shrinking the business, selling underperforming assets and transforming the company into the king of cooking oils. Bunge operates the world’s largest network of crushing facilities, processing everything from soybeans to canola and sunflower seeds to make frying oil and animal feed.

Russia’s invasion of Ukraine last year threw global commodity markets into disarray, boosting crop prices and cutting off supply. That created the perfect conditions for trading houses that buy, sell and transport the world’s agricultural resources — a market that’s dominated by the so-called ABCD quartet of Archer-Daniels-Midland Co., Bunge, Cargill Inc. and Louis Dreyfus Co.

The industry’s recovery has opened up options for Bunge.

“As we told the shareholders, everything is on the table,” Heckman said in an interview earlier this year. “We will continue to consolidate the industry where it makes sense globally to fill in any weaknesses that we have and continue to build on our strengths.”

Glencore has been trying to break the ABCD stranglehold by growing its own crop operations through Viterra. The Swiss commodities giant acquired Viterra for C$6.1 billion (about $4.5 billion) in a 2012 deal that gave it grain assets in Canada and Australia. About four years later, it sold stakes totaling roughly half the business to Canada Pension Plan Investment Board and British Columbia Investment Management Corp.

Last year, Viterra spent $1.1 billion acquiring U.S.-focused trader Gavilon from Japan’s Marubeni Corp.

Talks about a potential deal between Viterra and Bunge come as Glencore separately battles to acquire Canadian miner Teck Resources Ltd. In April, it reiterated a $23 billion offer to buy Teck and said it was willing to go higher.