From https://metaculus.com/questions/15907/negative-ecb-interest-rate-before-2023/

The European Central Bank (ECB) deposit facility rate, a key component of the Eurosystem's monetary policy toolkit, allows commercial banks to deposit their excess reserves with the ECB. The deposit facility interest rate set by the ECB's Governing Council can be positive, negative, or zero, depending on the monetary policy stance. In Europe, the policy rate has been slightly negative from 2014 to 2022. See below for the rates since 2011:

Date (with effect from) Deposit facility interest rate 2023-03-22 3.00 2023-02-08 2.50 2022-12-21 2.00 2022-11-02 1.50 2022-09-14 0.75 2022-07-27 0.00 2019-09-18 -0.50 2016-03-16 -0.40 2015-12-09 -0.30 2014-09-10 -0.20 2014-06-11 -0.10 2013-11-13 0.00 2013-05-08 0.00 2012-07-11 0.00 2011-12-14 0.25 2011-11-09 0.50 2011-07-13 0.75 2011-04-13 0.50

In March 2023, the Governing Council has decided to increase the three key ECB interest rates by 50 basis points to ensure the timely return of inflation to the 2% medium-term target, given that inflation is projected to remain too high for too long. Recent financial market tensions have added uncertainty to ECB staff's macroeconomic projections. Inflation is expected to average 5.3% in 2023, 2.9% in 2024, and 2.1% in 2025. However, underlying price pressures continue to be strong. Growth in 2023 has been revised up to 1.0%, with growth expected to pick up to 1.6% in both 2024 and 2025. Given the current trajectory of inflation and the tightening of monetary policy, it appears unlikely that the ECB will return to negative interest rates in the near future, though if conditions similar to the early 2010s, with a continuously shrinking euro zone arise over the next decade, they may return:

Even if the current inflationary bout means it could be a while before Europe's central bankers need to use negative rates again, it is unlikely they will want to rule them out.

"They will always be spoken of as something that remains in the toolkit," said Rohan Khanna, strategist at UBS in London. "I am very doubtful anyone here is ready to say never again for negative rates."