FRED has added 9 series on overnight trading in the federal funds market from the New York Fed.

The effective federal funds rate (EFFR) is calculated as a volume-weighted median of overnight federal funds transactions of selected money market rates. EFFR is the rate associated with transactions at the 50th percentile of transaction volume. Transaction volume in the federal fund market and selected other percentiles are also available. Intraday highs and lows and the standard deviation series are provided as discontinued due to the changes to the calculation of the EFFR implemented at the beginning of March.