NEW YORK — Twelve major banks have tentatively agreed to pay $1.87 billion to settle allegations they colluded to fix prices and lock out competitors in the market for insurance-like products widely traded before the financial crisis, according to a lawyer for investors.

The deal would be one of the largest U.S. antitrust settlements, said Daniel Brockett, a lawyer representing a Los Angeles pension fund among other plaintiffs. He said the final terms need to be hammered out, and a judge would still need to approve the deal.

Bank of America, JPMorgan Chase, Citigroup and other banks met secretly to kill proposals that would put the trading of these insurance-like products onto an exchange through which they could be bought and sold like stocks and their prices made more transparent, according to a complaint filed in U.S District Court in New York.

“There was no central place to go for a stream of prices. You had to go to the banks and they controlled the business and they charged high prices,” said Brockett. An investor “basically had to pay what they wanted.”