About 50 lawsuits have been filed against Facebook, Nasdaq and underwriters of Facebook's May IPO. Aaron Lucchetti reports on Markets Hub. Photo: Reuters. .While investors face an uphill battle to recover losses, some legal experts said defendants in the arbitration claims and civil lawsuits face potentially large financial exposure given the stock's 47% slide since the IPO. In addition, securities lawyers who represent Facebook investors say they expect hundreds of arbitration claims to be launched against brokers and securities firms that pitched the company's shares.