MSRs are derived from their underlying mortgages and grants the Servicer ( who is purchasing the asset) the “right” to service the loan as per a Master Servicing Agreement
Currently almost 95%+ of the cases the Servicing rights are granted by the GSEs ( Fannie Mae or Freddie Mac) and GNMA ( Ginnie Mae) for pass thru Securitizations of US Residential Mortgages backed by these organizations
MSRs are a unique alternative asset class which are “positively correlated” to rates ( Mortgage) within a certain range – i.e., they act like “Short Bonds” with values potentially rising with increasing rates