Allen & Overy sued two Brazilian electricity generation companies in New York state court on Monday, seeking almost $1.3 million in unpaid legal bills tied to the firm's work on an arbitration case in 2013.

The Magic Circle firm said Multiner SA and Termeletrica Itapebi SA signed an Allen & Overy engagement letter in 2012 in connection with their arbitration against a German subsidiary of the heavy equipment maker Caterpillar Inc. But the Brazilian companies still haven't paid what they owe on six of nine invoices that were sent to them in 2013, the suit claims.

“Defendants have expressly acknowledged that the outstanding balances and outstanding fees are due and owing to A&O,” the complaint said.

According to its website, Multiner owns an oil and gas power plant and the largest wind farm in Brazil. There is little to no English-language information available about Termeletrica Itapebi, the other defendant, but documents posted on Multiner's website refer to it as a subsidiary.

Multiner has indicated in Portuguese-language financial statements from 2015 and 2018 that it has been obliged to pay some amount to the Caterpillar subsidiary involved in the arbitration, Caterpillar Motoren GmbH & Co. KG. The value of the judgment or settlement is not clear, but it is to be paid in installments through 2027.

Allen & Overy has previously sued at least one other client in Manhattan Supreme Court, where the Multiner action was filed. In 2017, it sued Qohelet Panama Corp. and another entity for more than $300,000 that was allegedly owed for work performed in connection with the development and financing of a solar power facility in Panama. That suit was rejected for technical flaws in January 2018.

Patrick Bonner of Menz Bonner Komar & Koenigsberg, who is representing Allen & Overy in the firm's collection suit, did not respond to comment requests on Tuesday. Neither did a spokesman for Allen & Overy.

Representatives for Multiner SA did not immediately return messages submitted through email and the company's website.