Seneca Mortgage Servicing LLC, which entered the business just three years ago, has decided to outsource the monthly processing of loans to Nationstar, a sign that private-equity firms are no longer so enamored with the returns generated by mortgage servicing rights. According to a statement issued by Nationstar, it will service all of Seneca’s $50 billion portfolio and any rights Seneca might obtain going forward. Moreover, it will take control of the firm’s Depew platform in upstate New York. No terms were disclosed. However, according to interviews with servicing advisors, Seneca – whose backers include The Blackstone Group, EJF Capital and Arbor Commercial Mortgage – may not be...