MONTREAL — Embattled engineering giant SNC-Lavalin is facing its second-class action lawsuit in months after a Toronto firm said it is seeking $1.5-billion on behalf of investors outside of Quebec who saw the value of their asset plummet.Rochon Genova LLP announced the lawsuit Wednesday, alleging the Montreal-based company violated securities law by misrepresenting that it had adequate controls and procedures to ensure accurate disclosure and financial reporting.“When a company repeatedly highlights its strong governance practices to the investing public, revelations of serious misconduct cause damage to the company’s reputation and, in turn, substantial harm to its investors,” lawyer John Archibald said in a news release.The claim arises from alleged payments made by SNC-Lavalin to members, associates, and agents of the Gaddafi regime to secure contracts for infrastructure projects in Libya.The allegations have not been proven in court.[np-related]It follows a $250-million claim filed in March on behalf of investors in Quebec. Quebec law firm Siskinds, Desmeules filed a claim in Quebec Superior Court in March against the company and certain of its former officers and directors.That proposed class includes all persons who acquired securities of SNC between March 13, 2009 and Feb. 28, 2012. It alleges SNC-Lavalin made statements that were “materially false and misleading” in relation to its code of conduct, legal compliance, and internal controls. It also alleged that some senior executives “were engaged in unlawful activities in Libya” contrary to its statements.SNC didn’t immediately respond to this latest legal challenge. But it denied all liability in respect of the claims alleged in the earlier class-action and vowed to defend itself.Shares of SNC-Lavalin dropped more than 20% on Feb. 28, wiping out more than $1.5-billion of market value after the company disclosed the launching of an investigation into $35-million of undocumented payments.Nearly $3.5-billion has been wiped from the company’s value since SNC’s shares peaked at $59.97. They lost 28 cents to $36.77 in afternoon trading Wednesday on the Toronto Stock Exchange.The engineering and construction giant’s initial review led to it finding $56-million of payments to unidentified foreign agents.The company insists that none of the funds were directed to Libya.Former CEO Pierre Duhaime approved payments suggested by former executive vice-president Riadh Ben Aissa, SNC’s former head of construction, who is in a Swiss jail on suspicion of corrupting a public official, fraud and money laundering tied to his dealings in North Africa.Duhaime, Ben Aissa and former controller Stephane Roy have lost their jobs with SNC-Lavalin.The lawsuit was brought on behalf of all SNC-Lavalin investors, excluding residents of Quebec, who purchased securities of SNC-Lavalin between Feb. 1, 2007 and Feb. 28, 2012 or who purchased debentures of the company through the company’s June 2009 prospectus offering.Analyst Maxim Sytchev of AltaCorp Capital said the lawsuits will have no short-term impact on perceptions about SNC or its share performance.He noted the suits could drag on for a long time, if they ever get certified by the courts.“For the time being this is not an issue,” he said in an interview.“Here it looks like they’re being sued for an event that only recently became apparent even to the people on the inside,” he said, adding there is no proof of payments to Libya.SNC-Lavalin removed $900-million worth of Libyan projects from its backlog in 2010 amid the civil war in the North African country.Chairman Gwyn Morgan and interim CEO Ian Bourne tried to calm jittery investors attending its annual meeting last week, telling them client confidence remains strong despite intense turmoil that has tarnished its name.The RCMP executed search warrants at SNC-Lavalin’s headquarters at the request of Swiss police.However, Bourne said he wouldn’t be surprised if police aren’t able to use their powers to shed more light on events.