BNP Paribas faces possible insider trading probe French prosecutors have opened a preliminary inquiry into suspected insider trading by officials at BNP Paribas, said a person with knowledge of the investigation. Should the investigation go forward it threatens to further damage the reputation of France's largest bank by market capitalisation, which earlier this year was hit with a record $8.9bn fine for US sanctions violations. The inquiry is being launched by the "le parquet national financier," a body started last year specialising in corruption and tax evasion. Eliane Houlette, its head, said this year that it would be a financial "strike force." Under French law a preliminary investigation does not mean that any evidence of wrongdoing has been found or that charges will necessarily be brought. BNP Paribas declined to comment on the reports. The investigation "could take months" because of its complex nature, said a person close to the affair, adding that it was still in its "very early stages." The person declined to give details on exactly who was being investigated. The same person refused to say if the inquires would be related to trading that took place at the time of the US fine, where market making news was usually leaked in the press rather than communicated officially. The investigation comes at an awkward time for BNP, which is attempting to draw a line under a difficult year. Top management were pushed into early retirement and the bank suffered its worst ever quarterly loss because of the US fine. After months of negotiations the bank pleaded guilty to processing billions of dollars of transactions for groups in Sudan, Iran and Cuba between 2002 and 2012. It was given a one-year ban on clearing some dollar transactions. BNP said as a result it would create a supervisory committee as well as a conduct committee in charge of monitoring and possibly redrafting its policies in certain "sensitive" business sectors or countries. It also comes at a sensitive time for the industry plagued by allegations of misconduct. Last week $4.3bn in penalties were meted out by US, Swiss and UK regulators over allegations of rigging in the $5.3tn-a-day foreign exchange market. Bank of Tokyo-Mitsubishi (BTMU) on Tuesday was ordered by Ben Lawsky, New York state's superintendent of financial services, to pay $315m for "misleading regulators" over transactions with Iran, Sudan and Myanmar that violated US sanctions law. The Department of Financial Services found that BTMU employees "pressured" a consultant, PwC, into "removing key warnings to regulators in a supposedly "objective" report . . . [on] BTMU's illicit conduct on behalf of those sanctioned countries and entities." It demanded that BTMU fire a compliance officer, Tetsuro Anan, and ban two other employees from working with New York banks. French weekly newspaper Le Canard Enchaîné first reported on Wednesday that French prosecutors had opened a preliminary probe targeting officials at BNP, without going into further detail. "Le parquet national financier" was created after the scandal last year over Jérôme Cahuzac, the former budget minister who was revealed to have held a secret Swiss bank account.