Oct. 30 (Bloomberg) -- Richardson Partners Financial Ltd., a Toronto-based investment adviser, failed to disclose conflicts as it pressed unsuitable investments to clients, investors claimed in a lawsuit.

The suit, filed Oct. 7 in Ontario Superior Court by 23 people, an estate and nine personal holding companies, claims Richardson and investment adviser Clarke Steele bought on their behalf securities, including Opti Canada Inc., in which Richardson had a undisclosed interest.

Opti Canada shares plunged 97 percent to 63 Canadian cents on March 11 from a high of C$25.05 on June 17, 2008, as the oil sands developer declined with other energy stocks, along with the price of crude amid a recession.

“Opti Canada Inc. was related to or associated with Richardson and/or Steele and Richardson and Steele failed to disclose this fact,” the investors claim in the court filing. “Richardson and Steele were in conflict of interest.”

Richardson was among the underwriters who bought C$40 million of Opti stock for resale, as the company raised money for exploration. Richardson was also among the companies that led Opti’s initial public offering in 2004, raising C$300 million.

Tammy Clark, a Richardson spokeswoman, didn’t immediately respond to a request for comment.

The investors asked a judge to rescind all their trades. Additionally, or in the alternative, they sought C$19 million in compensatory and punitive damages.

The case is Between Clifford Atkinson and Richardson Partners Financial Ltd. File no.: CV-09-388591. Ontario Superior Court of Justice (Toronto).

To contact the reporter on this story: Joe Schneider in Toronto at jschneider5@bloomberg.net

Last Updated: October 30, 2009 11:21 EDT