Saying it aims "to disrupt the status quo" in the banking industry, GMAC announced the launch of Ally Bank on Friday.
Ally's rates on savings and money market accounts will always be among the best nationwide, Al de Molina, GMAC's chief executive officer, said in a press release.
Ally also offers a certificate of deposit that lets customers withdraw money at any time without a fee.
"Unlike other banks, which depend on fees as a business model, we want to make money with customers, not off customers," de Molina said.
Though it already operated a bank, mostly to serve GM dealers and customers, GMAC said it would move those people to Ally, which it developed to attract retail deposits.
GMAC has been hurt by a sharp decline in its auto and home lending businesses. It became a bank holding company in December and received $5 billion of capital through the Treasury Department's Troubled Asset Relief Program.
But it is still struggling, and another government infusion is imminent.
The recent stress tests pegged its capital hole at $11.5 billion.
