Deutsche Bank could end up coughing up more than $2bn (£1.33bn, €1.87bn) to UK and US authorities over the manipulation of a key interest rate benchmark.

That figure will be more than what any other bank has been fined over rate rigging, Reuters reported.

Authorities are preparing to announce a settlement as soon as 23 April.

Negotiations also are expected to result in a guilty plea by a unit of the German bank, the news agency added.

Libor and related benchmarks are used to fix interest rates for trillions of dollars' worth of loans the world over, from student loans and mortgages to credit cards and complex derivatives.

Authorities involved include the Financial Conduct Authority (FCA), the US Department of Justice, New York's Department of Financial Services (DFS) and the Commodity Futures Trading Commission (CFTC) in Washington.

Pursued by Reuters, officials for the Justice Department, the New York regulator and the CFTC refused to comment.

The FCA could not immediately be reached.

Renee Calabro, a spokeswoman for Deutsche Bank, said in a statement: "We continue to work with the authorities that are reviewing interbank offered rates matters."

On 22 April, the German lender said it expects to report litigation costs of about €1.5bn for the first-quarter 2015.

Despite the costs, the bank said it will be profitable in the first-quarter and that it will report near record revenues.

Earlier, The Wall Street Journal reported that Deutsche will announce a settlement of over $2.15bn in response to charges that its employees attempted to manipulate interest rates.

Germany's top lender is among the last major banks to settle with authorities following an investigation of the London interbank offered rate, or Libor.

In 2012, UBS agreed to pay $1.5bn to authorities in a global settlement and Barclays paid $453m.