Series is calculated as the spread between 3-Month Treasury Bill: Secondary Market Rate (ROUND_B1_CLOSE_13WK_2M)) and Effective Federal Funds Rate (https://fred.stlouisfed.org/series/EFFRM). Starting with the update on June 21, 2019, the Treasury bond data used in calculating interest rate spreads is obtained directly from the U.S. Treasury Department (https://www.treasury.gov/resource-center/data-chart-center/interest-rates/Pages/TextView.aspx?data=yield).

View the spread between 3-month LIBOR and Treasury bills, which indicates perceived credit risk.

For further information regarding treasury constant maturity data, please refer to the H.15 Statistical Release notes (https://www.federalreserve.gov/releases/h15/default.htm) and the Treasury Yield Curve Methodology (https://home.treasury.gov/policy-issues/financing-the-government/interest-rate-statistics/treasury-yield-curve-methodology).

For further information regarding treasury constant maturity data, please refer to the H.15 Statistical Release notes (https://www.federalreserve.gov/releases/h15/default.htm) and the Treasury Yield Curve Methodology (https://home.treasury.gov/policy-issues/financing-the-government/interest-rate-statistics/treasury-yield-curve-methodology).

For further information regarding treasury constant maturity data, please refer to the H.15 Statistical Release notes (https://www.federalreserve.gov/releases/h15/default.htm) and the Treasury Yield Curve Methodology (https://home.treasury.gov/policy-issues/financing-the-government/interest-rate-statistics/treasury-yield-curve-methodology).

Series Is Presented Here As Two Variables--(1)--Original Data, 1920-1934 (2)--Original Data, 1931-1969. Data For 1920-March 1934 Are For The Average Daily Figures For U.S. Treasury Three-Six Month Notes And Certificates. Beginning February 1931, Data Are Averages Of Weekly Rates Discount On New Treasury Three Month Bills. Data For 1920-1921 Are For Average Daily Figures For The Week Nearest The 15Th Of The Month. Data For April-June 1928 Are Based On Certificates Of Six To Nine Months Maturity. Source: Direct From The The Federal Reserve Board; Also Banking And Monetary Statistics, P. 460. This NBER data series m13029a appears on the NBER website in Chapter 13 at http://www.nber.org/databases/macrohistory/contents/chapter13.html. NBER Indicator: m13029a

Series is calculated as the spread between 6-Month Treasury Bill: Secondary Market Rate (https://fred.stlouisfed.org/series/TB6MS) and Effective Federal Funds Rate (https://fred.stlouisfed.org/series/FEDFUNDS).

This series was constructed by the Bank of England as part of the Three Centuries of Macroeconomic Data project by combining data from a number of academic and official sources. For more information, please refer to the Three Centuries spreadsheet at https://www.bankofengland.co.uk/statistics/research-datasets. Users are advised to check the underlying assumptions behind this series in the relevant worksheets of the spreadsheet. In many cases alternative assumptions might be appropriate. Users are permitted to reproduce this series in their own work as it represents Bank calculations and manipulations of underlying series that are the copyright of the Bank of England provided that underlying sources are cited appropriately. For appropriate citation please see the Three Centuries spreadsheet for guidance and a list of the underlying sources.