Eurotunnel has suspended trading in the group's shares on the Paris and London stock exchanges.
The company, which recently announced its first annual profit of 1 million (£0.8 million) after reaching an agreement with creditors, said the suspension is provisional, pending an important announcement.
Paris-based Eurotunnel said in a statement: "Pending an important announcement that is expected during the course of today, Groupe Eurotunnel has requested that trading in all of the group's securities be provisionally suspended on Euronext Paris and the London Stock Exchange."
At the beginning of April, the company said revenues had improved on a high-speed southern England link to the continent and a restructuring plan.
In 2007, revenues increased by six per cent to 775 million (£618 million), while shuttle revenues increased by eight per cent to 500 million (£399 million).
The company is expected to announce a rights issue soon relating to the restructuring.