Alstom denies the allegations, which it says are not new
French engineering group Alstom has denied that it is being investigated over allegations that it paid bribes to help win overseas contracts.
Responding to an article in the Wall Street Journal, an Alstom spokesman said the report "was based on hypotheses and speculation".
"Alstom stresses that no legal procedure has targeted the company in the matter of corruption," he added.
Alstom is alleged to have paid to win contracts in Asia and South America.
The Wall Street Journal alleges that the bribes were paid between 1995 and 2003 from "shell companies" based in Switzerland and neighbouring Liechtenstein.
It says the money was then give to people working for Alstom in Singapore, Indonesia, Venezuela and Brazil.
In one specific case, the newspaper alleges that Swiss and Brazilian police have met to discuss suspicions that Alstom paid $6.8m (£3.5m) to help win a $45m contract to expand Sao Paulo's underground network.
The Alstom spokesman added that the Wall Street Journal article simply "reiterates statements or insinuations which had already appeared several months ago in various articles published in Switzerland and Germany".
He further said that while a unspecified number of people employed by the firm were being questioned by Swiss authorities, they were being interviewed as witnesses in an investigation that did not target Alstom.
Alstom makes everything from trains to power stations.
It enjoys annual revenues of more than 14bn euros ($21.5bn; £11bn).