The Swiss stock exchange (SWX) has opened an official investigation into PubliGroupe's half-yearly results, which were released last September.
Switzerland's leading media company is suspected of having committed a potential violation of the exchange's Listings Rules.
The SWX opened a preliminary inquiry last September after the Lausanne-based company announced a six-month drop in net profits of 93 per cent to SFr8 million ($4.8 million).
Under SWX regulations, companies are required to make information public, which might influence the value of its stock. PubliGroupe's individual share price fell from SFr450 to SFr280 in the period between the board of directors meeting and the release of the half-yearly results.
The length of the investigation has not been fixed, and no information will be made public while the proceedings are underway.
Last week PubliGroupe posted a "substantial deficit" of SFr185 million for 2001, down from a profit of SFr140 million in 2000.
It blamed the loss on difficult economic conditions, over-rapid and excessive developments in the online sector, and a loss-making investment in a United States advertising agency network.
swissinfo with agencies