Greensill Capital has challenged the German banking regulator, BaFin, over the transparency of financial accounting at the Bremen-based Greensill Bank after its banking operations were shut down and criminal proceedings were reportedly launched.

The defence comes as court documents released by the NSW Supreme Court on Thursday revealed one of Greensill’s insurers, the Bond & Credit Company, launched an investigation last year into the relationship between one of its employees, Greg Brereton, and Greensill Capital.