Contracts referencing SOFR are usually based on an average of daily interest rates over a given period of time. These averages of SOFR are quite smooth and can be easily referenced in financial contracts, as demonstrated by the growing use of SOFR in futures, swaps, and floating-rate notes. SOFR futures and OIS, and the many SOFR floating rate notes that have been issued all use either a compound or linear average of SOFR over a fixed period of time as the floating rate paid under the terms of the contract, not a single day’s realization of SOFR.
Overnight rates in the repo market are inherently somewhat volatile, and the dynamics that generate much of the volatility are well-known and somewhat predictable. For example, settlements of Treasury securities typically cause fluctuations in rates throughout the month, and in particular on coupon settlement dates at the middle and end of months, while balance sheet management by some repo market participants contributes to temporary volatility around quarter-end dates.
While these features of the Treasury repo market can contribute to some day-to-day volatility of SOFR, this volatility has little impact on the averages of SOFR that are used in financial contracts. These averages of SOFR are less volatile than SOFR itself.
For more, see the ARRC’s Frequently Asked Questions Version: January 31, 2019