Regulators also want more OTC trades shifted onto exchanges, something the merger might have achieved.

SEFs are included in the Dodd-Frank U.S. financial reform bill that requires far more OTC swaps to run through exchanges and clearinghouses.

Regulators want to run many more OTC products, such as derivatives, that previously changed hands privately through clearing houses to stabilize the financial system.

Regulators want to run many more OTC products that previously changed hands privately, such as derivatives, through clearing houses to stabilize the financial system.