The Bank of England (BoE) has confirmed that its reforms to the SONIA interest rate benchmark will take effect on Monday 23 April 2018.

The reforms will result in:

  • the BoE taking on the end-to-end administration, including the calculation and publication of SONIA;
  • the coverage of SONIA being broadened to include overnight unsecured transactions negotiated bilaterally as well as those arranged via brokers, using the BoE’s Sterling Money Market Data Collection as the data source;
  • the averaging methodology for calculating SONIA changing to a volume-weighted trimmed mean; and
  • the publication of SONIA moving to 09:00 on the business day following that to which the rate pertains.

View SONIA reform to be implemented on 23 April 2018, 16 October 2017