Before acquiring a target company, an element of due diligence will have been carried out to investigate the target and assess the viability and financial liquidity of the target company. The findings of due diligence checks may have led to an adjustment of the purchase price or the alteration of the terms of the share purchase agreement. If you have engaged a professional (i.e. an accountant) to undertake due diligence on a target and that professional missed a key document or failed to advise on a specific point then you may have a claim for professional negligence, particularly if the professionals failures led to you or your business to suffer substantial losses.