We are not certain of its origin, but certainly a significant decrease in SOFR activity last week. The lowest in the "SOFR First" era at LCH and lowest in 5 weeks for the ISDA reported figures. But the ISDA reported figures indicated a relative increase with respect to LIBOR.
It is not clear what the origin of this is. One potential explanation is market moving out of LIBOR but not to SOFR.
CME futures on BSBY provide a view of market price discovery of SOFR v credit sensitive rates. For those that have not yet agreed on the fallback for legacy LIBOR trades, that opens a window on valuation impacts.
This makes Marc's cautionary tale published in January 2020 edition of Risk even more tangible. It is now possible, to some extend, to measure the exercise value of the protocol option. Marc mentioned the "Fallback protocol as an option" in the past, in particular in the blog "ISDA Fallback as an option".
For the (low volume for BSBY and SOFR) trades on the September 2023 contract (first after USD-LIBOR cessation), the spread LIBOR-SOFR is 27 bps and the spread BSBY-SOFR is 19 bps. The first one is roughly in line with the CME Eurodollar futures fallback using ISDA/Bloomberg spread (26.161 bps), the second one provides the cost of protocol signature for a September 2023 fixing: losing or making 8 bps. Lets wait for more volume on the longer term part to assess more of the value transfer. We will try to provide more data on BSBY in a forthcoming blog.