FRANKFURT (Reuters) -Germany has fined Citigroup nearly 13 million euros ($13.94 million) for lapses in its trading system controls, the nation's bank regulator said on Thursday, as its consumer protection division imposed its largest penalty ever.

It is related to a mishap in 2022 involving $1.4 billion in mistaken sell orders in equities, an event that riled markets and for which Citigroup was already fined 61.6 million pounds($78.24 million) by British authorities in May.

Citi on May 2, 2022 processed a $444 billion order that was meant to amount to just $58 million, prompting $1.4 billion in mistaken sell orders, according to British regulators' findings.

Authorities in both Britain and Germany have said the error was a single trader's input mistake, known as a "fat-finger" error.

German regulator BaFin said that Citigroup Global Markets Europe AG had "failed to ensure that erroneous orders were not transmitted".

Such mistakes can "trigger or at least contribute to market disruption," BaFin said.

Citigroup in Frankfurt said it had taken "steps to strengthen our systems and controls, and remains committed to ensuring full regulatory compliance".

"We are pleased to resolve this matter from more than two years ago, which arose from an individual error that was identified and corrected within minutes," Citigroup said.

($1 = 0.9325 euros)

($1 = 0.7873 pounds)

(Reporting by Tom Sims and Alexander Huebner, Editing by Madeline Chambers and Shinjini Ganguli)