Mortgage servicer Nationstar Mortgage Holdings (NSM) unofficially confirmed it has plans to continue growing its mortgage servicing portfolio when it announced Monday that the company and its Nationstar Capital Corp. subsidiary plan to sell $400 million in senior notes due in 2021.

The company said net proceeds could be used for future acquisitions and transfers of mortgage servicing portfolios. On the same day, the company said it has closed on the purchase of MSRs with an unpaid principal balance of $97 billion from Bank of America. "This servicing portfolio consists of rights to service loans that are owned, insured or guaranteed by Fannie Mae, Freddie Mac, and Ginnie Mae," Nationstar said.

The public offer will be used to fund numerous transactions, including the acquisition of residential mortgage servicing assets from Bank of America (BAC), National Association and other third parties, Nationstar said in a statement.

The Lewisville-based company spent the past year acquiring MSRs.

Most recently, the company priced two servicer advanced receivable transactions at $300 million. The two deals are part of a larger offering, estimated at $900 million, that Nationstar announced in January.

Nationstar's servicing portfolio currently includes 1.8 million residential mortgages with an unpaid principal balance in excess of $300 billion, according to the firm's own figures.