Bank of America executives improperly concealed billions of dollars in losses and billions in bonuses paid by Merrill Lynch before a shareholder vote on their proposed merger, Ohio’s attorney general argued in a class-action suit he said was among the largest in history.

Attorney General Richard Cordray filed a complaint against Bank of America and its executives late Friday, the first since Ohio was awarded the lead role in a lawsuit that includes the state’s two largest public employee pension funds and the Teacher Retirement System of Texas.

The complaint, filed in US District Court in New York, includes allegations made in previous complaints against BofA. It includes new details about conversations and communications between BofA and Merrill Lynch executives that have surfaced in media reports, congressional testimony and with the Securities and Exchange Commission.