Technology website VentureBeat said in a report on Wednesday Apple was working with "at least one partner, Swatch" on a smartwatch project, citing an unnamed source.
A spokeswoman for Swatch Group said on Thursday the report was unfounded. She said the only business relationship Swatch Group had with mobile phone makers was as a supplier of integrated circuits and other electronic components.
Signs are mounting that Apple, which landed huge successes with its iPhone mobile phones and iPad tablets, is preparing the launch of an iWatch, following the commercialisation of smartwatches by rivals such as Samsung and LG Electronics.
Swatch Group shares rose 2 percent to 510 Swiss francs by 1045 GMT, outperforming a 0.2 percent higher European sector index.
"I have no doubt that Swatch is up on the back of these press reports - against a rather dull market and sector performance today," Exane BNP Paribas analyst Luca Solca said, adding smartwatches seemed to be at the centre of attention in the investment community.
JPMorgan analysts said in a note the VentureBeat article looked questionable because they would find it surprising if Swatch launched products under its own brands to link them to Apple applications, as the report had suggested.
"One of (Swatch Chief Executive Nick) Hayek's main concerns over smartwatches, repeatedly stated in analysts conference calls in the last six months, is the possible dependence on software and applications from other companies," they said.
Hayek told Reuters in an interview on Tuesday he was not interested in teaming up with a tech group to develop a smartwatch.
© Thomson Reuters 2014