Cash Rate

Bank of England

SONIA sterling overnight index average

View on United Kingdom desk

3.73%

+0.00 pp (+0.01%)

As of Sep 14, 2026 | Daily (sterling overnight market rate)

Mean
2.89%
Median
3.43%
Min
0.04% Dec 31, 2020
Max
8.61% Apr 30, 1998
DateRate
Sep 14, 20263.73
Aug 28, 20263.73
Jul 31, 20263.73
Jun 30, 20263.73
May 29, 20263.73
Apr 30, 20263.73
Mar 31, 20263.73
Feb 27, 20263.73
Jan 30, 20263.73
Dec 31, 20253.73
Nov 28, 20253.97
Oct 31, 20253.97
Sep 30, 20253.97
Aug 29, 20253.97
Jul 31, 20254.22
Jun 30, 20254.22
May 30, 20254.21
Apr 30, 20254.46
Mar 31, 20254.46
Feb 28, 20254.46
Jan 31, 20254.70
Dec 31, 20244.70
Nov 29, 20244.70
Oct 31, 20244.95

About SONIA

SONIA is the sterling overnight index average — the main sterling risk-free rate (IUDSOIA). Current: 3.73% on Sep 14, 2026. The Bank of England publishes it; it does not set it. Transaction-based overnight market rate, including the 2018 reform, from 1997.

Chart and long-run stats use month-ends; the headline is the latest daily print. From Jan 31, 1997 to Sep 14, 2026 (357 months): mean 2.89%, median 3.43%; low 0.04% (Dec 31, 2020), high 8.61% (Apr 30, 1998). Not Bank Rate, and not a mortgage or savings rate.

Source: Bank of England Statistical Database, series IUDSOIA (SONIA). Licence: SONIA data licensed under the Open Government Licence v3.0 and copyright the Governor and Company of the Bank of England. The trade marks “Bank of England” and “SONIA” are registered trade marks of the Bank of England (terms). Files: data/raw/boe-sonia.csv.

Reading this series

SONIA is the sterling overnight index average, the risk-free reference rate for sterling and the benchmark that replaced LIBOR in that role. The Bank of England publishes it from transaction data, but it does not set it: it is a market rate reflecting unsecured overnight borrowing. This page uses Bank of England series IUDSOIA, under the Open Government Licence, with history from 1997 that includes the 2018 reform of the benchmark.

Because it is a market rate, SONIA moves daily and is not stepped. The headline is the latest daily print; the chart and the long-run statistics use month-ends, which keeps the drawn series readable. Read the value with its as-of date, then the "versus the previous reading" line for the most recent change. Mean, median, low and high summarise the observations in this build, not an official average. Chart and Table present one series two ways, range buttons filter the window, and Explore loads zoom and pan only when asked. SONIA is not Bank Rate, and it is not a mortgage or savings rate.