Saracens are facing major sanctions over a potential breach of salary cap regulations, after Premiership Rugby confirmed the club had not declared all co-investment arrangements between players and owner Nigel Wray before they were revealed by this newspaper. In a statement issued on Wednesday night, Premiership Rugby Ltd (PRL) said Wray's business links with his star players, including England captain Owen Farrell, Maro Itoje and the Vunipola brothers, will now be formally 'reviewed'. The decision to investigate will come as a major blow to Saracens and Wray, who had sought to play down the outcome of a four-month Sportsmail investigation. Saracens are facing major sanctions over a potential breach of salary cap regulations That expose had raised serious questions about whether Saracens and Wray - who is worth £315m - were operating within the £7m salary cap, when in the last three years Wray had struck up businesses with at least five members of his all-conquering squad. When a list of questions about these arrangements with players was put to the club, they responded that 'the Club readily complies with Premiership Rugby salary regulations and information relating to remuneration is declared to the salary cap manager.' And later, in an open letter by Wray, he said that 'the Club is open and transparent with the salary cap manager and we proactively disclose co-investments when they occur, even though we are under no obligation to do so'. However, it has now become clear that there may be a cause for concern for PRL surrounding what had and had not been declared. The statement PRL issued last night would suggest Saracens are in serious trouble, with a points deduction a possible sanction. A spokesman for PRL said: 'Under the Salary Regulations, clubs are required to supply information to the Premiership Rugby Salary Cap Manager on any arrangements between a Connected Party and a Player which might constitute payment or a benefit in kind. 'Saracens had not at the time of recent media speculation shared with the Premiership Rugby Salary Cap Manager details of all the co-investment arrangements between Connected Parties and Players. 'The information now received from the club and various parties will be reviewed. Premiership Rugby will make no further comment at this stage.' It is understood that the move by PRL has come in light of significant pressure from other member clubs, who were adamant that a tough stance should be taken. At a board meeting on Tuesday, the matter is thought to have been raised by club chairmen keen to get answers from PRL, who had until now remained tight-lipped on the findings of Sportsmail's investigation. At this stage, it is not clear which arrangements had not been declared prior to Sportsmail's investigation being published, and Saracens put it down to a 'minor internal oversight'. Under the ownership of Wray, Saracens have become one of the dominant forces in European rugby, winning the Premiership three times in the last four seasons and being crowned double European champions. Owner Nigel Wray went into business with players including Mako and Billy Vunipola The club, who were previously investigated in relation to the salary cap, boasted eight members of England's 2019 Six Nations squad with Elliot Daly due to join from Wasps. However, eyebrows were raised by the findings of this newspaper's investigation, and several former players responded by calling for a full and transparent investigation. In addition to going into business with Farrell and Itoje, property entrepreneur Wray has similar arrangements with Mako and Billy Vunipola and Richard Wigglesworth, and has also co-owned houses with former Saracens players. Earlier this week Sportsmail revealed that PRL salary cap manager Andrew Rogers is arranging interviews with current and former Saracens players to interrogate on their financial dealings with the club. A statement from Saracens last night said: 'Unprompted, we invited Premiership Rugby’s salary cap manager into the Club to openly discuss matters related to player salaries. Whilst co-investments are not part of the salary regulations, we disclosed these transactions in good faith and indeed divulged more information than was necessary. 'Separately, following a minor internal oversight, Premiership Rugby was provided with details relating to some of these agreements. We remain confident that we comply with the salary regulations and will continue to support the entrepreneurial spirit and future of our players.' Players including England stars Owen Farrell (pictured) also went into business with Wray All rights reserved for this news site dailymail and under his responsibility