The Federal Reserve is investigating whether mortgage payments are owed on properties that are now worth less than they were at the time of the transaction.
The Fed is also looking at whether payments are made to borrowers who have defaulted on their mortgages, and whether some payments are being withheld, The New York Times reported Thursday.
In some cases, the payments may be denied outright, the Times reported.
The newspaper cited people familiar with the investigation.
The Federal Deposit Insurance Corporation is conducting a separate probe into the matter.
In the meantime, the Fed is taking steps to avoid future issues.
The central bank has been reviewing its policy to keep its balance sheet intact, a person familiar with that review said, the Wall Street Journal reported.
While there is no suggestion the Fed has intentionally withheld payments, it is taking these steps to minimize the risk that a borrower could lose their home due to a default, according to the paper.
The person added that the Fed was considering whether it could impose penalties on banks and lenders that were delinquent on their mortgage payments, the newspaper reported.