The report by Viceroy Research published last week focused on tech and manufacturing firm Hexagon. Hexagon's chairman, Ola Rollen, worked for Hexagon but also set up the investment firm, Greenbridge.

It said when Hexagon invested in startup tech and industrial companies, Greenbridge, invested earlier, front-running the investments.

The report, focusing on one particular investment in the manufacturing company Divergent, said it was made at an unfair advantage.

In a statement sent to Reuters late on Monday, Greenbridge said that it is not a related party to Hexagon and did not break any accounting rules in dealings with Hexagon.

Hexagon has repeatedly declined to comment.

On Sunday, Greenbridge said it had not front-run any investments made by Hexagon. Greenbridge said it invested in Divergent in April 2023, four months after Hexagon invested in December, "and on an arm's length basis".

Greenbridge told Reuters late on Monday it made a $15 million investment through the shell company, or special purpose vehicle called Blackbird Holdings Sàrl, to invest in startup companies.

However, the shell company was inactive in December when Hexagon invested in Divergent. It did not raise money to invest in Divergent until March 29, the statement said.

Then, Greenbridge invested $15 million alongside other investors to a total of $65 million that they together used to invest in Divergent on 4 April 2023, the statement on Monday said.

(Reporting by Nell Mackenzie and Dhara Ranasinghe; editing by Barbara Lewis)

By Nell Mackenzie