A crucial $15 billion piece of funding is still missing in the complex financial structure that ChemChina plans to use in its mega-acquisition of Swiss agribusiness giant Syngenta AG. China National Agrochemical Corp. (CNAC), a wholly owned subsidiary of ChemChina, will use a three-layered structure involving six special-purpose vehicles to raise capital for the deal, according to Caixin. The cornerstone to the highly leveraged financing arrangement is $15 billion to be injected into CNAC. But it remains unclear who will provide these funds, according to people close to the bank lenders. The proposed $43 billion takeover is the biggest overseas offer ever made by a Chinese company. It has received attention worldwide in part because it needs the approval of Chinese, American and European authorities.