Ally Financial amended its initial public offering registration to sell up to $100 million in common stock.

Ally, which made a variety of adjustments to its IPO prospectus, has been mostly in runoff mode in respect to its mortgage holdings with the IPO focused on putting its automotive financial services business into overdrive.

The company said it expects to continue to develop Ally Bank, however, according to Friday's regulatory filing with the Securities and Exchange Commission.

The automotive finance company and bank holding company will be traded on the New York Stock Exchange under the ticker ALLY.

Underwriters for the IPO include Citigroup (C), Goldman, Sachs & Co. (GS), JPMorgan Chase (JPM), Morgan Stanley (MS), Barclays Capital and Deutsche Bank Securities.

Ally is in the process of winding down its warehouse lending business and its mortgage unit, ResCap, entered Chapter 11 bankruptcy protection in May. Several companies have expressed interest in buying its assets.

Ally's mortgage operations had $17.1 billion in assets at June 30. It plans to continue some mortgage operations via Ally Bank, whose assets include conforming and government-insured residential mortgage loans.

In the first six months of 2012, Ally originated or purchased $14.5 billion of U.S. residential mortgage loans. Conforming and government-insured residential mortgage loans comprised 92.8% of those originations.

Since the onset of the housing crisis, Ally has reduced its mortgage assets from $135.1 billion in 2006 to $17.1 billion at June 30, primarily through the run-off and divestiture of noncore businesses and assets, according to a regulatory filing.

"The loans originated in our mortgage operations are currently comprised primarily of high credit quality conforming, government-insured and prime jumbo residential mortgage loans. At June 30, 2012, we held reserves of $124 million for potential repurchase obligations for loans we sold to counterparties," the company said in an SEC filing.

The Treasury Department, which bailed out Ally and other large financial corporations during the 2008 financial crisis, holds more than 118 million shares of Ally's preferred stock valued at more than $5.9 billion.

In connection with the public offering, the Treasury Department plans to convert 58.8 million shares of preferred stock into common stock. The amount of stock the Treasury would receive will depend on the common stock public offering price, Ally said.