Short answer
Often both parties. The subservicer performing the work generally needs servicer licenses where the loans sit, and many states also license the master servicer or MSR owner even though it never touches a payment. The split must be checked per state, not assumed from the contract. Cornerstone Licensing licenses both sides of subservicing relationships and keeps each party's map in Atlas.
Subservicing contracts allocate work, not licensing obligations; states do that, and they do it inconsistently. The clean cases are the states that plainly license whoever conducts servicing activity, which catches the subservicer, and the states that define servicing to include holding servicing rights, which catches the owner. The messy middle includes exemption structures that depend on the owner's charter, since bank-owned MSRs are often exempt where investor-owned MSRs are not, and states that expect the owner to be licensed before it can even board loans with a licensed subservicer.
Diligence runs both directions: owners should verify the subservicer's license coverage matches the portfolio's geography before boarding, and subservicers should confirm the owner holds whatever the states require of it, because either side's gap surfaces in the other's exam. Cornerstone Licensing maps the obligation split for each arrangement, files the missing licenses on whichever side needs them, and maintains both portfolios in Atlas with the boarding-state list reconciled to actual coverage.
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