By Tim Hepher
PARIS (Reuters) - Shares in Europe's Airbus <AIR.PA> fell on Thursday after Le Monde newspaper reported the United States had opened an investigation into allegations of corruption, raising the stakes of probes already under way in Britain and France.
The French newspaper said Airbus could face record fines of several billion euros as a result of the overall case, which dates back to 2016.
Airbus shares were down by around 6 percent in mid-session trading, having at one stage fallen by as much as 9 percent.
The U.S. Department of Justice was not immediately available for comment.
Airbus said it was already co-operating with UK and French investigations triggered in 2016 by its own internal audit.
In a statement, it said it had previously disclosed that U.S. authorities had sought information on the case and added, "Here, too, Airbus is co-operating with the U.S. authorities in close coordination with the (British) SFO and (French) PNF."
Airbus is in the throes of a board-driven management clearout designed to demonstrate cooperation and change the face of the company in the hopes of winning a judicial settlement on the use of middlemen, a practise that its executives say ended in 2014.
At the centre of the case is a decades-old system of agents run from a now-disbanded headquarters unit which at its height involved some 250 agents across parts of the world and several hundreds of millions of euros of fees per year, insiders say.
In October, Reuters reported that the board had hastened the departure of finance director Harald Wilhelm, prompting his surprise decision to resign even while acknowledging he had started the audit and halted the system of payments.
People familiar with the matter have said the clearout extends across the senior ranks of the company and, coupled with a wave of retirements, led to an unprecedented speed of change.
Others have been placed under pressure to leave, prompting arguments over who should take responsibility for the tightly controlled system, multiple sources close to the case said.
Airbus said in February it had been asked to supply information to U.S. authorities about conduct at the centre of a UK and French probe into the use of middlemen in jetliner sales, potentially drawing the United States into the corruption case.
In a separate case, Airbus said in 2017 it had reported inaccuracies in filings to U.S. regulators under a part of U.S. arms exports controls governing the use of commissions.
People familiar with the case say progress has been slowed by French rules limiting the ability of foreign agencies to collect information or directly question French citizens.
Several sources said U.S. authorities had demonstrated frustration at the process and taken steps to remind European partners about their interest in the case.
(Reporting by Tim Hepher; Additional reporting by Sudip Kar-Gupta; Editing by Keith Weir)