Hamdi Ulukaya, owner of Greek yogurt company Chobani, received sour news Tuesday: According to the New York Post, his ex-wife Ayse Giray has filed a lawsuit claiming she is owed a 53% stake in the yogurt brand. 

Giray, a medical doctor, says in her complaint that the couple founded the business together in 1997 when they used her credit and personal assets to open the cheese-making company Eurphrates in upstate New York. At the time, Giray claims Ulukaya promised her 53% of the business. 

Though the couple divorced in 1999, they remained business partners through 2003. Giray claims that she gave Ulukaya $300,000 in 2003 in order to help Eurphrates expand to dairy products--namely yogurt. Between 1997 and 2003, Giray says she gave Ulukaya a total of $500,000. Instead of expanding Eurphrates, Giray alleges Ulukaya went behind her back with the money to purchase a separate plant that later became the Chobani headquarters.

In a recent Inc. 5000 applicant profile, Ulukaya claims he took out his own loan to start Chobani. Yet when Ulukaya purchased and converted the old Kraft yogurt plant, Giray says he promised her that their original deal would apply to Chobani as well as Eurphrates, only to retract the promise in 2011 when she asked for her share. Giray’s attorney Richard Feldman told The Post that they are also seeking access to Chobani’s accounting records to assess further damages.

The private and fast-growing company--2011 revenues were more than $600 million and its three-year growth rate was 2,662%--sponsored Team USA at the London Olympics and opened its first brick-and-mortar location in New York last month.

Ulukaya did not immediately respond to a request for comment.