London-based private equity firm Duke Street has written down its investment in legal services firm Parabis Group to zero, it has emerged, with the personal injury specialist continuing to explore sale options.

Duke Street bought a stake in the Parabis, which provides legal advice on personal injury and insurance matters, in a deal that valued the company at between £150 million to £200 million in 2012. The deal was one of the first buyouts of a law firm after the government allowed external investment in firms in 2012.