(Bloomberg) -- Banks are finding allies in Brussels with their call for extra time to adopt a new euro benchmark lending rate as Europe tries to put a spate of rigging scandals behind it.

Some European Union lawmakers are searching for a way to give banks more time to replace the existing benchmark -- the euro overnight index average, or Eonia -- with a new rate produced by the European Central Bank. A smooth transition is critical, because about 22 trillion euros ($25.3 trillion) of derivative contracts are tied to Eonia.

Time is short. The use of Eonia will be restricted at the start of 2020 because it doesn’t meet EU standards, and the ECB may not start publishing its replacement -- the euro short-term rate, or Ester -- until October 2019. That short window makes an extension of Eonia’s life span essential, according to Caroline Nagtegaal, a Dutch lawmaker in the European Parliament who has proposed a legislative fix to give banks more time to make the switch.

“An extension of the transitional period by two years allows for minimal market disruption and reduces risks for the financial system,” Nagtegaal told lawmakers earlier this month.

Time Crunch

Lenders in an industry working group on euro risk-free rates whose members include BNP Paribas SA and Deutsche Bank AG chose Ester as their preferred replacement for Eonia. The move is part of a global shift to new rates after banks paid billions of dollars in fines for rigging the London interbank offered rate and other widely used benchmarks.

The working group wants at least two more years to make the transition to Ester, in line with the parliament’s draft amendment. A proposal has been made to EU member states, which also must approve legislation, for three extra years, the people said.

The challenge for lawmakers is that there’s not much time left to push bills through before the European Parliament breaks in April for elections the following month. The European Commission, which initiates all EU legislation, has said there’s currently no proposal on the table to open up the bloc’s benchmarks law and extend the use of Eonia.

That means the delay will have to be attached to a bill already in the pipeline. Both the parliament and member states are pursuing two main options. The first, to which Nagtegaal attached her rider, is an overhaul of the EU’s regulatory agencies. The second is a reform of EU low-carbon benchmarks, according to people familiar with the matter.

Either way, there’s no guarantee these bills will cross the finish line in time. The parliament’s Economic and Monetary Affairs Committee is scheduled to discuss the carbon benchmarks bill on Thursday.

©2018 Bloomberg L.P.