ING U.S. Inc., an insurance unit of the largest Dutch financial-services company, expects to get gross proceeds of about $600 million from a planned U.S. initial public offering.

Parent ING Groep NV will also sell stock in the offering, according to a regulatory filing today. The filing didn’t specify how much in proceeds the parent expects. ING filed for the IPO in November using a $100 million placeholder amount.

ING Groep was ordered by the European Union to sell insurance operations, its U.S. online bank and a Dutch mortgage lender before the end of this year as a condition for approval of a 2008 bailout. The U.S. unit, led by ex-American International Group Inc. executive Rodney Martin, competes with MetLife Inc. and Prudential Financial Inc. selling savings products as workers rely less on their employers for pensions.

ING U.S. also said it may issue about $1.1 billion in debt after the IPO is completed, consisting of $700 million long-term junior subordinated debt securities and $400 million in senior unsecured notes.

The U.S. unit has about 13 million customers and offers savings products and annuities in addition to life insurance, according to the filing. Revenue fell 1.1 percent to $9.62 billion last year.

Morgan Stanley, Goldman Sachs Group Inc. and Citigroup Inc. are leading the sale. Evercore Partners Inc. is among the underwriters added in the latest filing.