Indebted family conglomerate Al-Gosaibi sued Maan Al-Sanea, the head of the Saad Group in a case involving allegations of $10 billion in loan irregularities, according to court documents. The lawsuit filed in New York State Supreme Court on Wednesday by Ahmad Hamad Al-Gosaibi and Bros (AHAB) is part of running dispute and responds to an earlier complaint filed against it by Dubai-based bank Mashreq over irregular forex trades. Regulators and bankers are grappling with the fallout from debt restructuring at Al-Gosaibi and Saad Group, seen as the biggest blow to hit the Middle East since the start of the financial crisis. In June, Al-Gosaibi said it had discovered evidence of substantial financial irregularities within its financial services arm but did not offer any specific information. The Saad-Al-Gosaibi crisis has already had far-reaching consequences for the financial sector in the Gulf, home to the biggest economies of the Middle East. Saad has been forced to sell off parts of its international investments, including a stake in UK construction company Berkeley Group. Sanea, a big stakeholder in bank HSBC, has had his personal accounts. The case is Mashreqbank PSC against Ahmed Hamad Al-Gosaibi and Brothers Company in New York State Supreme Court. A dispute between two leading Saudi business families has erupted with Al-Gosaibi group filing a $10 billion fraud lawsuit against Saad group, the Financial Times reported on Friday. AHAB alleged in the suit filed in a New York court that billionaire Sanea used “forged or falsified documents” to arrange loans from a Gosaibi financial unit and took the money for his own needs.