TPG and J.C. Flowers have teamed up to bid for the insurance subsidiary, which could be valued at $500 million to $900 million, said one of the people familiar with the situation, who is not permitted to speak to media and wished to remain anonymous.

Goldman Sachs is handling the sale of the business, the people said.

Allstate, Goldman, Resolution and TPG declined to comment. J.C. Flowers was not immediately available for comment.

A growing number of insurers have been selling their life and annuity businesses because the low interest rate environment makes it more difficult to run these businesses profitably.

In April, AXA SA sold its U.S. life insurance unit to Protective Life Corp for $1.06 billion.

In December, Sun Life Financial Inc sold its variable annuity business to Delaware Life Holdings, a company owned by clients and shareholders of Guggenheim Partners. The Sun Life unit was valued at $1.35 billion.

Resolution Life and J.C. Flowers had also bid for the Sun Life unit but lost to Delaware, sources had told Reuters at the time .

(Reporting by Jessica Toonkel; Editing by Gary Hill)

By Jessica Toonkel