DECATUR, ILL. — Archer Daniels Midland Co. is negotiating the sale of its stake in Gruma S.A.B. de C.V., according to a number of sources.

Gruma, which is 23.2% owned by ADM, said in a formal statement, it “has unofficial knowledge of a potential interest of a third-party to acquire the minority stake that Archer-Daniels-Midland Company holds in Gruma and in some of its subsidiaries.”

Gruma has a market capitalization of $1.8 billion, which would put the value of ADM’s holdings at about $418 million. Gruma is the world’s largest producer and marketer of corn flour and tortillas with operations in Mexico, the United States, Central America, South America, Europe, Asia and Australia.

Beyond its direct stake in Gruma, ADM owns 20% of six U.S. corn flour mills and one in Italy, held by a joint venture with ADM. Through still another joint venture with Gruma, ADM has a 40% share in nine Mexican wheat flour mills. The holdings were delineated in the fiscal 2012 10-K of ADM, filed Aug. 27 with the Securities and Exchange Commission.

Bloomberg News said ADM has reached a preliminary agreement to sell its Gruma stake to Fernando Chico Pardo, a Mexican businessman. An ADM spokesperson told Bloomberg the “preliminary agreement is non-binding and is subject to notation of a definitive agreement.“

The news followed by a few days an announcement by GrainCorp Ltd., Sydney, Australia, that it has received “an indicative, non-binding proposal from ADM stating it is prepared to make an offer to acquire the outstanding shares in GrainCorp at a price of $11.75 per share in cash, subject to a number of conditions including due diligence, exclusivity and approval by the ADM board.”

Gruma said further information will be forthcoming if and when the company is “formally informed about this possible transaction and its terms and conditions.”

In that event, the company noted that the transaction “would be subject to the bylaws of Gruma and to the applicable legal regulations, as well as to possible rights of first refusal that other shareholders may be entitled to.”