Cameron Winklevoss, co-founder of the Gemini crypto exchange, tweeted what he described as a “final offer” in the debt-restructuring talks over the bankrupt digital-asset firm Genesis, bringing months of negotiations and mediation to a head with a plan for $1.5 billion in forbearance payments and fresh loans.

On Monday, Winklevoss posted to Twitter an “Open Letter to Barry Silbert,” the founder of Digital Currency Group (DCG), which owns Genesis as well as the giant crypto asset manager Grayscale. (CoinDesk is also a holding.)

In the letter, Winklevoss bemoaned delays on the part of DCG to come up with a satisfactory plan to repay Genesis creditors, including customers of Gemini’s Earn program. DCG also has missed a payment of $630 million to Genesis.

Winklevoss tweeted a document titled “Best and Final Offer – July 3, 2023,” with the outlines of a plan that calls for $1.465 billion of payments and loans denominated in dollars, bitcoin and ether. The deadline to agree to the deal is 4 p.m. on July 6, according to the letter.

“I write to inform you that your games are over,” Winklevoss wrote in the letter. “In addition to dragging out a resolution, they have ballooned professional fees to over $100 million, all of which have gone to lawyers and advisors at the expense of creditors and Earn users.”

In a January court filing, Genesis had listed more than $3 billion in claims to its top 50 creditors. According to Winklevoss, some $1.2 billion is owed to Earn users.

Efforts to reach DCG for comment were not immediately successful.

In the letter, Winklevoss wrote that the consequences of failing to agree to “this deal” by the deadline could include lawsuits against DCG and Silbert personally, as well as pushing to put DCG into default and working on a “non-consensual” debt-repayment plan.

Elizabeth Napolitano contributed reporting for this article.