Bank of England

SONIA sterling overnight index average

View on United Kingdom desk

3.73%

+0.00 pp (+0.01%)

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

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

About SONIA

SONIA is the sterling overnight index average — the main sterling risk-free rate (IUDSOIA). Current: 3.73% on 14 Sep 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 31 Jan 1997 to 14 Sep 2026 (357 months): mean 2.89%, median 3.43%; low 0.04% (31 Dec 2020), high 8.61% (30 Apr 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.

About this desk

The India desk leads with the RBI repo rate, read from the BIS central bank policy rate series for India, then US, UK and Japan rates. The repo rate is the rate at which the Reserve Bank of India lends to banks against government securities; the BIS series is the overnight repo rate from 2001 and the Bank Rate before that, stitched into one comparable policy measure and drawn as daily steps. It is a policy rate, not a mortgage or deposit rate.

All desks carry the same series in a different order, so the numbers match the hub. Values are republished with attribution to the BIS, and this page is not an official BIS publication. The build ingests no Indian retail deposit series, so none is shown; gaps are left open rather than estimated. This is not financial advice, and readings may lag their source.