ZURICH (Reuters) - The Swiss bourse has opened an investigation into whether UBS
It was not clear how long the investigation by its SIX Exchange Regulation arm would take, it said, adding that it would provide no more information while the case was still open.
UBS dismissed the allegation, saying: "There is no basis for this investigation."
The bank said it took its disclosure responsibilities seriously, had complied with all legal requirements and had upheld its own standards for disclosure quality and timeliness.
SIX did not say what exactly it was investigating, but ad hoc publicity rules require companies to inform the market promptly of developments that could affect the price of their securities.
In both of the cases it cited, intense media speculation had preceded official announcements from the bank.
In December, UBS announced it had been hit with a $1.5 billion bill from U.S., UK and Swiss regulators and admitted to fraud in order to settle charges of manipulating global benchmark interest rates.
Last October, it unveiled plans to cut 10,000 staff and wind down its fixed-income business, returning to its private banking roots as it adapts to tough capital rules that make it harder to turn a profit from trading.
Exchange operator SIX spokesman Alain Bichsel said initial checks had warranted opening a full investigation into UBS's disclosures. Such probes happen regularly, normally to check if companies have met formal requirements and deadlines, he said.
Potential sanctions range from a simple warning to delisting, but violating ad hoc publicity rules typically triggers fines of up to 10 million Swiss francs ($11.2 million).
Bichsel said the strongest sanction was actually a statement that the exchange had launched a formal investigation.(Reporting by Rupert Pretterklieber and Michael Shields; Editing by Kevin Liffey)