The partners then struck a deal to unload their holdings with private energy-trading company CEFC, which appeared at the time to be a fast-growing investor with global ambitions and Beijing backing. CEFC, founded in 2002 and based in Shanghai, has been expanding internationally in recent years. Earlier this year, though, whatever official support CEFC enjoyed appeared to be crumbling. In March, The Wall Street Journal reported Ye Jianming, the company’s leader, was under investigation in China. Mr. Ye, who made his early fortune as an oil man, was seen to have close ties to China’s military and intelligence. Mr. Ye’s whereabouts are unknown. Since his disappearance, banks have called in credit lines, and CEFC has sought to raise money in China. CEFC has been unable to complete some of its biggest plans, including a major expansion in the Czech Republic, the purchase of around 20% of New York financial-services firm Cowen Group Inc. and the purchase of a Portuguese insurer. CEFC couldn’t immediately be reached.All that put the fate of a sale of the Rosneft stake in doubt. Late Friday, Glencore said it and the Qatar fund had terminated their deal with CEFC and dissolved their own partnership agreement. Glencore said the two would subsequently each hold their respective equity stakes in Rosneft separately. A subsidiary of the Qatar fund would take ownership of roughly 14% of Rosneft, giving the fund an overall 18.93% stake in Rosneft. Glencore, meanwhile, will exit with 0.57%. Exact financial terms between the partners and the banks involved weren’t disclosed. Glencore said it would receive 3.7 billion euros, or $4.43 billon, in the transaction. A person familiar with the matter said the cash would be used to pay back debt that helped finance the original deal. It was unclear whether Glencore Chief Executive Ivan Glasenberg would remain on Rosneft’s board. Representatives for Qatar couldn’t be reached immediately for comment. —Scott Patterson in London contributed to this article.