A quartet of outside law firms and accountants will help probe how banks ended up taking control of more than $2bn at a key China Evergrande Group subsidiary.

Last week, the highly indebted Chinese real-estate developer and its Evergrande Property Services Group unit said lenders had enforced their rights over 13.4bn yuan, or about $2.1bn, of bank deposits pledged by the subsidiary to guarantee third-party borrowing.