Nationstar Mortgage Services (NMS) closed on a deal to buy $16.1 billion in servicing rights previously owned by Aurora Bank.
The rights are tied to loans bundled into Fannie Mae and Freddie Mac pools, according to a financial filing.
In March, Aurora agreed to sell $63 billion in MSRs to Nationstar.
Nationstar said it expects to close on the remaining servicing rights on June 26.
While many banks are reducing their servicing portfolios, nonbank firms like Nationstar are expanding.
Should Nationstar win the bid, it will become the largest nonbank servicer in the U.S.