The FRED series Total Credit Market Debt Owed by Domestic Financial Sectors - REITs is now known as Real Estate Investment Trusts; Credit Market Instruments; Liability.
The source series id is FL644104005.Q.
This series appears in Table L.1. For further information see the assistance provided in the guide to the Flow of Funds at http://www.federalreserve.gov/apps/fof/.
Board of Governors of the Federal Reserve System (US), Real Estate Investment Trusts; Credit Market Instruments; Liability, Level [REITTCMDODFS], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/REITTCMDODFS/, June 2, 2015.