Citigroup Inc will pay $285 million to settle charges that its U.S. broker-dealer unit misled investors about a $1 billion mortgage bond deal, the U.S. Securities and Exchange Commission said on Wednesday.

The SEC said the collateralized debt obligation, or CDO, was tied to the U.S. housing market and that Citigroup bet against investors as the market showed signs of distress.

Citigroup settled with the SEC without admitting or denying the charges.

The SEC said it had settled separate charges against Credit Suisse's asset management unit, which was the collateral manager for the transaction, as well as the Credit Suisse portfolio manager primarily responsible for the transaction, Samir Bhatt.

Credit Suisse will pay $2.5 million to settle the case, the SEC said. The company also settled without admitting or denying the charges.